From 0ed38a64118f74f0e36ff9fbe9a98024a68971fb Mon Sep 17 00:00:00 2001
From: Chet Nieter <chet.nieter@gmail.com>
Date: Fri, 10 Feb 2023 16:56:11 -0500
Subject: [PATCH] Patching pybind11 to fix premature deletion of python objects

Patching pybind11 to fix premature deletion of python objects
created and wrapped in c++. This patch is based off an open
PR for pybind11.

https://github.com/pybind/pybind11/pull/2839
---
 CMake/External_pybind11.cmake                |   11 +
 Patches/pybind11/Patch.cmake                 |   31 +
 Patches/pybind11/cast.h                      | 1712 +++++++++++
 Patches/pybind11/detail/class.h              |  737 +++++
 Patches/pybind11/detail/common.h             | 1240 ++++++++
 Patches/pybind11/include/pybind11/pybind11.h | 1838 -----------
 Patches/pybind11/pybind11.h                  | 2883 ++++++++++++++++++
 7 files changed, 6614 insertions(+), 1838 deletions(-)
 create mode 100644 Patches/pybind11/Patch.cmake
 create mode 100644 Patches/pybind11/cast.h
 create mode 100644 Patches/pybind11/detail/class.h
 create mode 100644 Patches/pybind11/detail/common.h
 delete mode 100644 Patches/pybind11/include/pybind11/pybind11.h
 create mode 100644 Patches/pybind11/pybind11.h

diff --git a/CMake/External_pybind11.cmake b/CMake/External_pybind11.cmake
index b1d3fccc..62a52f21 100644
--- a/CMake/External_pybind11.cmake
+++ b/CMake/External_pybind11.cmake
@@ -6,12 +6,23 @@ if (PYTHON_EXECUTABLE)
   set(pybind_PYTHON_ARGS -DPYTHON_EXECUTABLE:FILEPATH=${PYTHON_EXECUTABLE})
 endif()
 
+# If a patch file exists, apply it
+set (pybind11_patch ${fletch_SOURCE_DIR}/Patches/pybind11)
+if (EXISTS ${pybind11_patch})
+  set(pybind11_PATCH_COMMAND ${CMAKE_COMMAND}
+      -Dpybind11_patch:PATH=${pybind11_patch}
+      -Dpybind11_source:PATH=${fletch_BUILD_PREFIX}/src/pybind11
+      -P ${pybind11_patch}/Patch.cmake
+    )
+endif()
+
 ExternalProject_Add(pybind11
   URL ${pybind11_url}
   URL_MD5 ${pybind11_md5}
   DOWNLOAD_NAME ${pybind11_dlname}
   ${COMMON_EP_ARGS}
   ${COMMON_CMAKE_EP_ARGS}
+  PATCH_COMMAND ${pybind11_PATCH_COMMAND}
   CMAKE_ARGS
     ${COMMON_CMAKE_ARGS}
     -DCMAKE_CXX_STANDARD=17
diff --git a/Patches/pybind11/Patch.cmake b/Patches/pybind11/Patch.cmake
new file mode 100644
index 00000000..4d48a97e
--- /dev/null
+++ b/Patches/pybind11/Patch.cmake
@@ -0,0 +1,31 @@
+#+
+# This file is called as CMake -P script for the patch step of
+# External_pybind11.cmake pybind11_patch and pybind11_source are defined on the command
+# line along with the call.
+#-
+
+# Patching files based off of open PR for pybind11
+# https://github.com/pybind/pybind11/pull/2839
+configure_file(
+  ${pybind11_patch}/cast.h
+  ${pybind11_source}/include/pybind11/
+  COPYONLY
+)
+
+configure_file(
+  ${pybind11_patch}/pybind11.h
+  ${pybind11_source}/include/pybind11/
+  COPYONLY
+)
+
+configure_file(
+  ${pybind11_patch}/detail/class.h
+  ${pybind11_source}/include/pybind11/detail
+  COPYONLY
+)
+
+configure_file(
+  ${pybind11_patch}/detail/common.h
+  ${pybind11_source}/include/pybind11/detail
+  COPYONLY
+)
diff --git a/Patches/pybind11/cast.h b/Patches/pybind11/cast.h
new file mode 100644
index 00000000..f9ab96a5
--- /dev/null
+++ b/Patches/pybind11/cast.h
@@ -0,0 +1,1712 @@
+/*
+    pybind11/cast.h: Partial template specializations to cast between
+    C++ and Python types
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#pragma once
+
+#include "detail/common.h"
+#include "detail/descr.h"
+#include "detail/type_caster_base.h"
+#include "detail/typeid.h"
+#include "gil.h"
+#include "pytypes.h"
+
+#include <array>
+#include <cstring>
+#include <functional>
+#include <iosfwd>
+#include <iterator>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+PYBIND11_WARNING_DISABLE_MSVC(4127)
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+template <typename type, typename SFINAE = void>
+class type_caster : public type_caster_base<type> {};
+template <typename type>
+using make_caster = type_caster<intrinsic_t<type>>;
+
+// Shortcut for calling a caster's `cast_op_type` cast operator for casting a type_caster to a T
+template <typename T>
+typename make_caster<T>::template cast_op_type<T> cast_op(make_caster<T> &caster) {
+    return caster.operator typename make_caster<T>::template cast_op_type<T>();
+}
+template <typename T>
+typename make_caster<T>::template cast_op_type<typename std::add_rvalue_reference<T>::type>
+cast_op(make_caster<T> &&caster) {
+    return std::move(caster).operator typename make_caster<T>::
+        template cast_op_type<typename std::add_rvalue_reference<T>::type>();
+}
+
+template <typename type>
+class type_caster<std::reference_wrapper<type>> {
+private:
+    using caster_t = make_caster<type>;
+    caster_t subcaster;
+    using reference_t = type &;
+    using subcaster_cast_op_type = typename caster_t::template cast_op_type<reference_t>;
+
+    static_assert(
+        std::is_same<typename std::remove_const<type>::type &, subcaster_cast_op_type>::value
+            || std::is_same<reference_t, subcaster_cast_op_type>::value,
+        "std::reference_wrapper<T> caster requires T to have a caster with an "
+        "`operator T &()` or `operator const T &()`");
+
+public:
+    bool load(handle src, bool convert) { return subcaster.load(src, convert); }
+    static constexpr auto name = caster_t::name;
+    static handle
+    cast(const std::reference_wrapper<type> &src, return_value_policy policy, handle parent) {
+        // It is definitely wrong to take ownership of this pointer, so mask that rvp
+        if (policy == return_value_policy::take_ownership
+            || policy == return_value_policy::automatic) {
+            policy = return_value_policy::automatic_reference;
+        }
+        return caster_t::cast(&src.get(), policy, parent);
+    }
+    template <typename T>
+    using cast_op_type = std::reference_wrapper<type>;
+    explicit operator std::reference_wrapper<type>() { return cast_op<type &>(subcaster); }
+};
+
+#define PYBIND11_TYPE_CASTER(type, py_name)                                                       \
+protected:                                                                                        \
+    type value;                                                                                   \
+                                                                                                  \
+public:                                                                                           \
+    static constexpr auto name = py_name;                                                         \
+    template <typename T_,                                                                        \
+              ::pybind11::detail::enable_if_t<                                                    \
+                  std::is_same<type, ::pybind11::detail::remove_cv_t<T_>>::value,                 \
+                  int>                                                                            \
+              = 0>                                                                                \
+    static ::pybind11::handle cast(                                                               \
+        T_ *src, ::pybind11::return_value_policy policy, ::pybind11::handle parent) {             \
+        if (!src)                                                                                 \
+            return ::pybind11::none().release();                                                  \
+        if (policy == ::pybind11::return_value_policy::take_ownership) {                          \
+            auto h = cast(std::move(*src), policy, parent);                                       \
+            delete src;                                                                           \
+            return h;                                                                             \
+        }                                                                                         \
+        return cast(*src, policy, parent);                                                        \
+    }                                                                                             \
+    operator type *() { return &value; }               /* NOLINT(bugprone-macro-parentheses) */   \
+    operator type &() { return value; }                /* NOLINT(bugprone-macro-parentheses) */   \
+    operator type &&() && { return std::move(value); } /* NOLINT(bugprone-macro-parentheses) */   \
+    template <typename T_>                                                                        \
+    using cast_op_type = ::pybind11::detail::movable_cast_op_type<T_>
+
+template <typename CharT>
+using is_std_char_type = any_of<std::is_same<CharT, char>, /* std::string */
+#if defined(PYBIND11_HAS_U8STRING)
+                                std::is_same<CharT, char8_t>, /* std::u8string */
+#endif
+                                std::is_same<CharT, char16_t>, /* std::u16string */
+                                std::is_same<CharT, char32_t>, /* std::u32string */
+                                std::is_same<CharT, wchar_t>   /* std::wstring */
+                                >;
+
+template <typename T>
+struct type_caster<T, enable_if_t<std::is_arithmetic<T>::value && !is_std_char_type<T>::value>> {
+    using _py_type_0 = conditional_t<sizeof(T) <= sizeof(long), long, long long>;
+    using _py_type_1 = conditional_t<std::is_signed<T>::value,
+                                     _py_type_0,
+                                     typename std::make_unsigned<_py_type_0>::type>;
+    using py_type = conditional_t<std::is_floating_point<T>::value, double, _py_type_1>;
+
+public:
+    bool load(handle src, bool convert) {
+        py_type py_value;
+
+        if (!src) {
+            return false;
+        }
+
+#if !defined(PYPY_VERSION)
+        auto index_check = [](PyObject *o) { return PyIndex_Check(o); };
+#else
+        // In PyPy 7.3.3, `PyIndex_Check` is implemented by calling `__index__`,
+        // while CPython only considers the existence of `nb_index`/`__index__`.
+        auto index_check = [](PyObject *o) { return hasattr(o, "__index__"); };
+#endif
+
+        if (std::is_floating_point<T>::value) {
+            if (convert || PyFloat_Check(src.ptr())) {
+                py_value = (py_type) PyFloat_AsDouble(src.ptr());
+            } else {
+                return false;
+            }
+        } else if (PyFloat_Check(src.ptr())
+                   || (!convert && !PYBIND11_LONG_CHECK(src.ptr()) && !index_check(src.ptr()))) {
+            return false;
+        } else {
+            handle src_or_index = src;
+            // PyPy: 7.3.7's 3.8 does not implement PyLong_*'s __index__ calls.
+#if PY_VERSION_HEX < 0x03080000 || defined(PYPY_VERSION)
+            object index;
+            if (!PYBIND11_LONG_CHECK(src.ptr())) { // So: index_check(src.ptr())
+                index = reinterpret_steal<object>(PyNumber_Index(src.ptr()));
+                if (!index) {
+                    PyErr_Clear();
+                    if (!convert)
+                        return false;
+                } else {
+                    src_or_index = index;
+                }
+            }
+#endif
+            if (std::is_unsigned<py_type>::value) {
+                py_value = as_unsigned<py_type>(src_or_index.ptr());
+            } else { // signed integer:
+                py_value = sizeof(T) <= sizeof(long)
+                               ? (py_type) PyLong_AsLong(src_or_index.ptr())
+                               : (py_type) PYBIND11_LONG_AS_LONGLONG(src_or_index.ptr());
+            }
+        }
+
+        // Python API reported an error
+        bool py_err = py_value == (py_type) -1 && PyErr_Occurred();
+
+        // Check to see if the conversion is valid (integers should match exactly)
+        // Signed/unsigned checks happen elsewhere
+        if (py_err
+            || (std::is_integral<T>::value && sizeof(py_type) != sizeof(T)
+                && py_value != (py_type) (T) py_value)) {
+            PyErr_Clear();
+            if (py_err && convert && (PyNumber_Check(src.ptr()) != 0)) {
+                auto tmp = reinterpret_steal<object>(std::is_floating_point<T>::value
+                                                         ? PyNumber_Float(src.ptr())
+                                                         : PyNumber_Long(src.ptr()));
+                PyErr_Clear();
+                return load(tmp, false);
+            }
+            return false;
+        }
+
+        value = (T) py_value;
+        return true;
+    }
+
+    template <typename U = T>
+    static typename std::enable_if<std::is_floating_point<U>::value, handle>::type
+    cast(U src, return_value_policy /* policy */, handle /* parent */) {
+        return PyFloat_FromDouble((double) src);
+    }
+
+    template <typename U = T>
+    static typename std::enable_if<!std::is_floating_point<U>::value && std::is_signed<U>::value
+                                       && (sizeof(U) <= sizeof(long)),
+                                   handle>::type
+    cast(U src, return_value_policy /* policy */, handle /* parent */) {
+        return PYBIND11_LONG_FROM_SIGNED((long) src);
+    }
+
+    template <typename U = T>
+    static typename std::enable_if<!std::is_floating_point<U>::value && std::is_unsigned<U>::value
+                                       && (sizeof(U) <= sizeof(unsigned long)),
+                                   handle>::type
+    cast(U src, return_value_policy /* policy */, handle /* parent */) {
+        return PYBIND11_LONG_FROM_UNSIGNED((unsigned long) src);
+    }
+
+    template <typename U = T>
+    static typename std::enable_if<!std::is_floating_point<U>::value && std::is_signed<U>::value
+                                       && (sizeof(U) > sizeof(long)),
+                                   handle>::type
+    cast(U src, return_value_policy /* policy */, handle /* parent */) {
+        return PyLong_FromLongLong((long long) src);
+    }
+
+    template <typename U = T>
+    static typename std::enable_if<!std::is_floating_point<U>::value && std::is_unsigned<U>::value
+                                       && (sizeof(U) > sizeof(unsigned long)),
+                                   handle>::type
+    cast(U src, return_value_policy /* policy */, handle /* parent */) {
+        return PyLong_FromUnsignedLongLong((unsigned long long) src);
+    }
+
+    PYBIND11_TYPE_CASTER(T, const_name<std::is_integral<T>::value>("int", "float"));
+};
+
+template <typename T>
+struct void_caster {
+public:
+    bool load(handle src, bool) {
+        if (src && src.is_none()) {
+            return true;
+        }
+        return false;
+    }
+    static handle cast(T, return_value_policy /* policy */, handle /* parent */) {
+        return none().release();
+    }
+    PYBIND11_TYPE_CASTER(T, const_name("None"));
+};
+
+template <>
+class type_caster<void_type> : public void_caster<void_type> {};
+
+template <>
+class type_caster<void> : public type_caster<void_type> {
+public:
+    using type_caster<void_type>::cast;
+
+    bool load(handle h, bool) {
+        if (!h) {
+            return false;
+        }
+        if (h.is_none()) {
+            value = nullptr;
+            return true;
+        }
+
+        /* Check if this is a capsule */
+        if (isinstance<capsule>(h)) {
+            value = reinterpret_borrow<capsule>(h);
+            return true;
+        }
+
+        /* Check if this is a C++ type */
+        const auto &bases = all_type_info((PyTypeObject *) type::handle_of(h).ptr());
+        if (bases.size() == 1) { // Only allowing loading from a single-value type
+            value = values_and_holders(reinterpret_cast<instance *>(h.ptr())).begin()->value_ptr();
+            return true;
+        }
+
+        /* Fail */
+        return false;
+    }
+
+    static handle cast(const void *ptr, return_value_policy /* policy */, handle /* parent */) {
+        if (ptr) {
+            return capsule(ptr).release();
+        }
+        return none().release();
+    }
+
+    template <typename T>
+    using cast_op_type = void *&;
+    explicit operator void *&() { return value; }
+    static constexpr auto name = const_name("capsule");
+
+private:
+    void *value = nullptr;
+};
+
+template <>
+class type_caster<std::nullptr_t> : public void_caster<std::nullptr_t> {};
+
+template <>
+class type_caster<bool> {
+public:
+    bool load(handle src, bool convert) {
+        if (!src) {
+            return false;
+        }
+        if (src.ptr() == Py_True) {
+            value = true;
+            return true;
+        }
+        if (src.ptr() == Py_False) {
+            value = false;
+            return true;
+        }
+        if (convert || (std::strcmp("numpy.bool_", Py_TYPE(src.ptr())->tp_name) == 0)) {
+            // (allow non-implicit conversion for numpy booleans)
+
+            Py_ssize_t res = -1;
+            if (src.is_none()) {
+                res = 0; // None is implicitly converted to False
+            }
+#if defined(PYPY_VERSION)
+            // On PyPy, check that "__bool__" attr exists
+            else if (hasattr(src, PYBIND11_BOOL_ATTR)) {
+                res = PyObject_IsTrue(src.ptr());
+            }
+#else
+            // Alternate approach for CPython: this does the same as the above, but optimized
+            // using the CPython API so as to avoid an unneeded attribute lookup.
+            else if (auto *tp_as_number = src.ptr()->ob_type->tp_as_number) {
+                if (PYBIND11_NB_BOOL(tp_as_number)) {
+                    res = (*PYBIND11_NB_BOOL(tp_as_number))(src.ptr());
+                }
+            }
+#endif
+            if (res == 0 || res == 1) {
+                value = (res != 0);
+                return true;
+            }
+            PyErr_Clear();
+        }
+        return false;
+    }
+    static handle cast(bool src, return_value_policy /* policy */, handle /* parent */) {
+        return handle(src ? Py_True : Py_False).inc_ref();
+    }
+    PYBIND11_TYPE_CASTER(bool, const_name("bool"));
+};
+
+// Helper class for UTF-{8,16,32} C++ stl strings:
+template <typename StringType, bool IsView = false>
+struct string_caster {
+    using CharT = typename StringType::value_type;
+
+    // Simplify life by being able to assume standard char sizes (the standard only guarantees
+    // minimums, but Python requires exact sizes)
+    static_assert(!std::is_same<CharT, char>::value || sizeof(CharT) == 1,
+                  "Unsupported char size != 1");
+#if defined(PYBIND11_HAS_U8STRING)
+    static_assert(!std::is_same<CharT, char8_t>::value || sizeof(CharT) == 1,
+                  "Unsupported char8_t size != 1");
+#endif
+    static_assert(!std::is_same<CharT, char16_t>::value || sizeof(CharT) == 2,
+                  "Unsupported char16_t size != 2");
+    static_assert(!std::is_same<CharT, char32_t>::value || sizeof(CharT) == 4,
+                  "Unsupported char32_t size != 4");
+    // wchar_t can be either 16 bits (Windows) or 32 (everywhere else)
+    static_assert(!std::is_same<CharT, wchar_t>::value || sizeof(CharT) == 2 || sizeof(CharT) == 4,
+                  "Unsupported wchar_t size != 2/4");
+    static constexpr size_t UTF_N = 8 * sizeof(CharT);
+
+    bool load(handle src, bool) {
+        handle load_src = src;
+        if (!src) {
+            return false;
+        }
+        if (!PyUnicode_Check(load_src.ptr())) {
+            return load_raw(load_src);
+        }
+
+        // For UTF-8 we avoid the need for a temporary `bytes` object by using
+        // `PyUnicode_AsUTF8AndSize`.
+        if (UTF_N == 8) {
+            Py_ssize_t size = -1;
+            const auto *buffer
+                = reinterpret_cast<const CharT *>(PyUnicode_AsUTF8AndSize(load_src.ptr(), &size));
+            if (!buffer) {
+                PyErr_Clear();
+                return false;
+            }
+            value = StringType(buffer, static_cast<size_t>(size));
+            return true;
+        }
+
+        auto utfNbytes
+            = reinterpret_steal<object>(PyUnicode_AsEncodedString(load_src.ptr(),
+                                                                  UTF_N == 8    ? "utf-8"
+                                                                  : UTF_N == 16 ? "utf-16"
+                                                                                : "utf-32",
+                                                                  nullptr));
+        if (!utfNbytes) {
+            PyErr_Clear();
+            return false;
+        }
+
+        const auto *buffer
+            = reinterpret_cast<const CharT *>(PYBIND11_BYTES_AS_STRING(utfNbytes.ptr()));
+        size_t length = (size_t) PYBIND11_BYTES_SIZE(utfNbytes.ptr()) / sizeof(CharT);
+        // Skip BOM for UTF-16/32
+        if (UTF_N > 8) {
+            buffer++;
+            length--;
+        }
+        value = StringType(buffer, length);
+
+        // If we're loading a string_view we need to keep the encoded Python object alive:
+        if (IsView) {
+            loader_life_support::add_patient(utfNbytes);
+        }
+
+        return true;
+    }
+
+    static handle
+    cast(const StringType &src, return_value_policy /* policy */, handle /* parent */) {
+        const char *buffer = reinterpret_cast<const char *>(src.data());
+        auto nbytes = ssize_t(src.size() * sizeof(CharT));
+        handle s = decode_utfN(buffer, nbytes);
+        if (!s) {
+            throw error_already_set();
+        }
+        return s;
+    }
+
+    PYBIND11_TYPE_CASTER(StringType, const_name(PYBIND11_STRING_NAME));
+
+private:
+    static handle decode_utfN(const char *buffer, ssize_t nbytes) {
+#if !defined(PYPY_VERSION)
+        return UTF_N == 8    ? PyUnicode_DecodeUTF8(buffer, nbytes, nullptr)
+               : UTF_N == 16 ? PyUnicode_DecodeUTF16(buffer, nbytes, nullptr, nullptr)
+                             : PyUnicode_DecodeUTF32(buffer, nbytes, nullptr, nullptr);
+#else
+        // PyPy segfaults when on PyUnicode_DecodeUTF16 (and possibly on PyUnicode_DecodeUTF32 as
+        // well), so bypass the whole thing by just passing the encoding as a string value, which
+        // works properly:
+        return PyUnicode_Decode(buffer,
+                                nbytes,
+                                UTF_N == 8    ? "utf-8"
+                                : UTF_N == 16 ? "utf-16"
+                                              : "utf-32",
+                                nullptr);
+#endif
+    }
+
+    // When loading into a std::string or char*, accept a bytes/bytearray object as-is (i.e.
+    // without any encoding/decoding attempt).  For other C++ char sizes this is a no-op.
+    // which supports loading a unicode from a str, doesn't take this path.
+    template <typename C = CharT>
+    bool load_raw(enable_if_t<std::is_same<C, char>::value, handle> src) {
+        if (PYBIND11_BYTES_CHECK(src.ptr())) {
+            // We were passed raw bytes; accept it into a std::string or char*
+            // without any encoding attempt.
+            const char *bytes = PYBIND11_BYTES_AS_STRING(src.ptr());
+            if (!bytes) {
+                pybind11_fail("Unexpected PYBIND11_BYTES_AS_STRING() failure.");
+            }
+            value = StringType(bytes, (size_t) PYBIND11_BYTES_SIZE(src.ptr()));
+            return true;
+        }
+        if (PyByteArray_Check(src.ptr())) {
+            // We were passed a bytearray; accept it into a std::string or char*
+            // without any encoding attempt.
+            const char *bytearray = PyByteArray_AsString(src.ptr());
+            if (!bytearray) {
+                pybind11_fail("Unexpected PyByteArray_AsString() failure.");
+            }
+            value = StringType(bytearray, (size_t) PyByteArray_Size(src.ptr()));
+            return true;
+        }
+
+        return false;
+    }
+
+    template <typename C = CharT>
+    bool load_raw(enable_if_t<!std::is_same<C, char>::value, handle>) {
+        return false;
+    }
+};
+
+template <typename CharT, class Traits, class Allocator>
+struct type_caster<std::basic_string<CharT, Traits, Allocator>,
+                   enable_if_t<is_std_char_type<CharT>::value>>
+    : string_caster<std::basic_string<CharT, Traits, Allocator>> {};
+
+#ifdef PYBIND11_HAS_STRING_VIEW
+template <typename CharT, class Traits>
+struct type_caster<std::basic_string_view<CharT, Traits>,
+                   enable_if_t<is_std_char_type<CharT>::value>>
+    : string_caster<std::basic_string_view<CharT, Traits>, true> {};
+#endif
+
+// Type caster for C-style strings.  We basically use a std::string type caster, but also add the
+// ability to use None as a nullptr char* (which the string caster doesn't allow).
+template <typename CharT>
+struct type_caster<CharT, enable_if_t<is_std_char_type<CharT>::value>> {
+    using StringType = std::basic_string<CharT>;
+    using StringCaster = make_caster<StringType>;
+    StringCaster str_caster;
+    bool none = false;
+    CharT one_char = 0;
+
+public:
+    bool load(handle src, bool convert) {
+        if (!src) {
+            return false;
+        }
+        if (src.is_none()) {
+            // Defer accepting None to other overloads (if we aren't in convert mode):
+            if (!convert) {
+                return false;
+            }
+            none = true;
+            return true;
+        }
+        return str_caster.load(src, convert);
+    }
+
+    static handle cast(const CharT *src, return_value_policy policy, handle parent) {
+        if (src == nullptr) {
+            return pybind11::none().release();
+        }
+        return StringCaster::cast(StringType(src), policy, parent);
+    }
+
+    static handle cast(CharT src, return_value_policy policy, handle parent) {
+        if (std::is_same<char, CharT>::value) {
+            handle s = PyUnicode_DecodeLatin1((const char *) &src, 1, nullptr);
+            if (!s) {
+                throw error_already_set();
+            }
+            return s;
+        }
+        return StringCaster::cast(StringType(1, src), policy, parent);
+    }
+
+    explicit operator CharT *() {
+        return none ? nullptr : const_cast<CharT *>(static_cast<StringType &>(str_caster).c_str());
+    }
+    explicit operator CharT &() {
+        if (none) {
+            throw value_error("Cannot convert None to a character");
+        }
+
+        auto &value = static_cast<StringType &>(str_caster);
+        size_t str_len = value.size();
+        if (str_len == 0) {
+            throw value_error("Cannot convert empty string to a character");
+        }
+
+        // If we're in UTF-8 mode, we have two possible failures: one for a unicode character that
+        // is too high, and one for multiple unicode characters (caught later), so we need to
+        // figure out how long the first encoded character is in bytes to distinguish between these
+        // two errors.  We also allow want to allow unicode characters U+0080 through U+00FF, as
+        // those can fit into a single char value.
+        if (StringCaster::UTF_N == 8 && str_len > 1 && str_len <= 4) {
+            auto v0 = static_cast<unsigned char>(value[0]);
+            // low bits only: 0-127
+            // 0b110xxxxx - start of 2-byte sequence
+            // 0b1110xxxx - start of 3-byte sequence
+            // 0b11110xxx - start of 4-byte sequence
+            size_t char0_bytes = (v0 & 0x80) == 0      ? 1
+                                 : (v0 & 0xE0) == 0xC0 ? 2
+                                 : (v0 & 0xF0) == 0xE0 ? 3
+                                                       : 4;
+
+            if (char0_bytes == str_len) {
+                // If we have a 128-255 value, we can decode it into a single char:
+                if (char0_bytes == 2 && (v0 & 0xFC) == 0xC0) { // 0x110000xx 0x10xxxxxx
+                    one_char = static_cast<CharT>(((v0 & 3) << 6)
+                                                  + (static_cast<unsigned char>(value[1]) & 0x3F));
+                    return one_char;
+                }
+                // Otherwise we have a single character, but it's > U+00FF
+                throw value_error("Character code point not in range(0x100)");
+            }
+        }
+
+        // UTF-16 is much easier: we can only have a surrogate pair for values above U+FFFF, thus a
+        // surrogate pair with total length 2 instantly indicates a range error (but not a "your
+        // string was too long" error).
+        else if (StringCaster::UTF_N == 16 && str_len == 2) {
+            one_char = static_cast<CharT>(value[0]);
+            if (one_char >= 0xD800 && one_char < 0xE000) {
+                throw value_error("Character code point not in range(0x10000)");
+            }
+        }
+
+        if (str_len != 1) {
+            throw value_error("Expected a character, but multi-character string found");
+        }
+
+        one_char = value[0];
+        return one_char;
+    }
+
+    static constexpr auto name = const_name(PYBIND11_STRING_NAME);
+    template <typename _T>
+    using cast_op_type = pybind11::detail::cast_op_type<_T>;
+};
+
+// Base implementation for std::tuple and std::pair
+template <template <typename...> class Tuple, typename... Ts>
+class tuple_caster {
+    using type = Tuple<Ts...>;
+    static constexpr auto size = sizeof...(Ts);
+    using indices = make_index_sequence<size>;
+
+public:
+    bool load(handle src, bool convert) {
+        if (!isinstance<sequence>(src)) {
+            return false;
+        }
+        const auto seq = reinterpret_borrow<sequence>(src);
+        if (seq.size() != size) {
+            return false;
+        }
+        return load_impl(seq, convert, indices{});
+    }
+
+    template <typename T>
+    static handle cast(T &&src, return_value_policy policy, handle parent) {
+        return cast_impl(std::forward<T>(src), policy, parent, indices{});
+    }
+
+    // copied from the PYBIND11_TYPE_CASTER macro
+    template <typename T>
+    static handle cast(T *src, return_value_policy policy, handle parent) {
+        if (!src) {
+            return none().release();
+        }
+        if (policy == return_value_policy::take_ownership) {
+            auto h = cast(std::move(*src), policy, parent);
+            delete src;
+            return h;
+        }
+        return cast(*src, policy, parent);
+    }
+
+    static constexpr auto name
+        = const_name("Tuple[") + concat(make_caster<Ts>::name...) + const_name("]");
+
+    template <typename T>
+    using cast_op_type = type;
+
+    explicit operator type() & { return implicit_cast(indices{}); }
+    explicit operator type() && { return std::move(*this).implicit_cast(indices{}); }
+
+protected:
+    template <size_t... Is>
+    type implicit_cast(index_sequence<Is...>) & {
+        return type(cast_op<Ts>(std::get<Is>(subcasters))...);
+    }
+    template <size_t... Is>
+    type implicit_cast(index_sequence<Is...>) && {
+        return type(cast_op<Ts>(std::move(std::get<Is>(subcasters)))...);
+    }
+
+    static constexpr bool load_impl(const sequence &, bool, index_sequence<>) { return true; }
+
+    template <size_t... Is>
+    bool load_impl(const sequence &seq, bool convert, index_sequence<Is...>) {
+#ifdef __cpp_fold_expressions
+        if ((... || !std::get<Is>(subcasters).load(seq[Is], convert))) {
+            return false;
+        }
+#else
+        for (bool r : {std::get<Is>(subcasters).load(seq[Is], convert)...}) {
+            if (!r) {
+                return false;
+            }
+        }
+#endif
+        return true;
+    }
+
+    /* Implementation: Convert a C++ tuple into a Python tuple */
+    template <typename T, size_t... Is>
+    static handle
+    cast_impl(T &&src, return_value_policy policy, handle parent, index_sequence<Is...>) {
+        PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(src, policy, parent);
+        PYBIND11_WORKAROUND_INCORRECT_GCC_UNUSED_BUT_SET_PARAMETER(policy, parent);
+        std::array<object, size> entries{{reinterpret_steal<object>(
+            make_caster<Ts>::cast(std::get<Is>(std::forward<T>(src)), policy, parent))...}};
+        for (const auto &entry : entries) {
+            if (!entry) {
+                return handle();
+            }
+        }
+        tuple result(size);
+        int counter = 0;
+        for (auto &entry : entries) {
+            PyTuple_SET_ITEM(result.ptr(), counter++, entry.release().ptr());
+        }
+        return result.release();
+    }
+
+    Tuple<make_caster<Ts>...> subcasters;
+};
+
+template <typename T1, typename T2>
+class type_caster<std::pair<T1, T2>> : public tuple_caster<std::pair, T1, T2> {};
+
+template <typename... Ts>
+class type_caster<std::tuple<Ts...>> : public tuple_caster<std::tuple, Ts...> {};
+
+/// Helper class which abstracts away certain actions. Users can provide specializations for
+/// custom holders, but it's only necessary if the type has a non-standard interface.
+template <typename T>
+struct holder_helper {
+    static auto get(const T &p) -> decltype(p.get()) { return p.get(); }
+};
+
+/// Another helper class for holders that helps construct derivative holders from
+/// the original holder
+template <typename T>
+struct holder_retriever {
+    static auto get_derivative_holder(const value_and_holder &v_h) -> decltype(v_h.template holder<T>()) {
+        return v_h.template holder<T>();
+    }
+};
+
+template <typename T>
+struct holder_retriever<std::shared_ptr<T>> {
+    struct shared_ptr_deleter {
+        // Note: deleter destructor fails on MSVC 2015 and GCC 4.8, so we manually
+        // call dec_ref here instead
+        handle ref;
+        void operator()(T *) {
+            gil_scoped_acquire gil;
+            ref.dec_ref();
+        }
+    };
+
+    static auto get_derivative_holder(const value_and_holder &v_h) -> std::shared_ptr<T> {
+        // If there's no trampoline class, nothing special needed
+        if (!v_h.inst->is_alias) {
+            return v_h.template holder<std::shared_ptr<T>>();
+        }
+
+        // If there's a trampoline class, ensure the python side of the object doesn't
+        // die until the C++ portion also dies
+        //
+        // The shared_ptr is always given to C++ code, so construct a new shared_ptr
+        // that is given a custom deleter. The custom deleter increments the python
+        // reference count to bind the python instance lifetime with the lifetime
+        // of the shared_ptr.
+        //
+        // This enables things like passing the last python reference of a subclass to a
+        // C++ function without the python reference dying.
+        //
+        // Reference cycles will cause a leak, but this is a limitation of shared_ptr
+        return std::shared_ptr<T>((T*)v_h.value_ptr(),
+            shared_ptr_deleter{handle((PyObject*)v_h.inst).inc_ref()});
+    }
+};
+
+/// Type caster for holder types like std::shared_ptr, etc.
+/// The SFINAE hook is provided to help work around the current lack of support
+/// for smart-pointer interoperability. Please consider it an implementation
+/// detail that may change in the future, as formal support for smart-pointer
+/// interoperability is added into pybind11.
+template <typename type, typename holder_type, typename SFINAE = void>
+struct copyable_holder_caster : public type_caster_base<type> {
+public:
+    using base = type_caster_base<type>;
+    static_assert(std::is_base_of<base, type_caster<type>>::value,
+                  "Holder classes are only supported for custom types");
+    using base::base;
+    using base::cast;
+    using base::typeinfo;
+    using base::value;
+
+    bool load(handle src, bool convert) {
+        return base::template load_impl<copyable_holder_caster<type, holder_type>>(src, convert);
+    }
+
+    explicit operator type *() { return this->value; }
+    // static_cast works around compiler error with MSVC 17 and CUDA 10.2
+    // see issue #2180
+    explicit operator type &() { return *(static_cast<type *>(this->value)); }
+    explicit operator holder_type *() { return std::addressof(holder); }
+    explicit operator holder_type &() { return holder; }
+
+    static handle cast(const holder_type &src, return_value_policy, handle) {
+        const auto *ptr = holder_helper<holder_type>::get(src);
+        return type_caster_base<type>::cast_holder(ptr, &src);
+    }
+
+protected:
+    friend class type_caster_generic;
+    void check_holder_compat() {
+        if (typeinfo->default_holder) {
+            throw cast_error("Unable to load a custom holder type from a default-holder instance");
+        }
+    }
+
+    bool load_value(value_and_holder &&v_h) {
+        if (v_h.holder_constructed()) {
+            value = v_h.value_ptr();
+            holder = holder_retriever<holder_type>::get_derivative_holder(v_h);
+            return true;
+        }
+        throw cast_error("Unable to cast from non-held to held instance (T& to Holder<T>) "
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+                         "(#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for "
+                         "type information)");
+#else
+                         "of type '"
+                         + type_id<holder_type>() + "''");
+#endif
+    }
+
+    template <typename T = holder_type,
+              detail::enable_if_t<!std::is_constructible<T, const T &, type *>::value, int> = 0>
+    bool try_implicit_casts(handle, bool) {
+        return false;
+    }
+
+    template <typename T = holder_type,
+              detail::enable_if_t<std::is_constructible<T, const T &, type *>::value, int> = 0>
+    bool try_implicit_casts(handle src, bool convert) {
+        for (auto &cast : typeinfo->implicit_casts) {
+            copyable_holder_caster sub_caster(*cast.first);
+            if (sub_caster.load(src, convert)) {
+                value = cast.second(sub_caster.value);
+                holder = holder_type(sub_caster.holder, (type *) value);
+                return true;
+            }
+        }
+        return false;
+    }
+
+    static bool try_direct_conversions(handle) { return false; }
+
+    holder_type holder;
+};
+
+/// Specialize for the common std::shared_ptr, so users don't need to
+template <typename T>
+class type_caster<std::shared_ptr<T>> : public copyable_holder_caster<T, std::shared_ptr<T>> {};
+
+/// Type caster for holder types like std::unique_ptr.
+/// Please consider the SFINAE hook an implementation detail, as explained
+/// in the comment for the copyable_holder_caster.
+template <typename type, typename holder_type, typename SFINAE = void>
+struct move_only_holder_caster {
+    static_assert(std::is_base_of<type_caster_base<type>, type_caster<type>>::value,
+                  "Holder classes are only supported for custom types");
+
+    static handle cast(holder_type &&src, return_value_policy, handle) {
+        auto *ptr = holder_helper<holder_type>::get(src);
+        return type_caster_base<type>::cast_holder(ptr, std::addressof(src));
+    }
+    static constexpr auto name = type_caster_base<type>::name;
+};
+
+template <typename type, typename deleter>
+class type_caster<std::unique_ptr<type, deleter>>
+    : public move_only_holder_caster<type, std::unique_ptr<type, deleter>> {};
+
+template <typename type, typename holder_type>
+using type_caster_holder = conditional_t<is_copy_constructible<holder_type>::value,
+                                         copyable_holder_caster<type, holder_type>,
+                                         move_only_holder_caster<type, holder_type>>;
+
+template <typename T, bool Value = false>
+struct always_construct_holder {
+    static constexpr bool value = Value;
+};
+
+/// Create a specialization for custom holder types (silently ignores std::shared_ptr)
+#define PYBIND11_DECLARE_HOLDER_TYPE(type, holder_type, ...)                                      \
+    PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)                                                  \
+    namespace detail {                                                                            \
+    template <typename type>                                                                      \
+    struct always_construct_holder<holder_type> : always_construct_holder<void, ##__VA_ARGS__> {  \
+    };                                                                                            \
+    template <typename type>                                                                      \
+    class type_caster<holder_type, enable_if_t<!is_shared_ptr<holder_type>::value>>               \
+        : public type_caster_holder<type, holder_type> {};                                        \
+    }                                                                                             \
+    PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
+
+// PYBIND11_DECLARE_HOLDER_TYPE holder types:
+template <typename base, typename holder>
+struct is_holder_type
+    : std::is_base_of<detail::type_caster_holder<base, holder>, detail::type_caster<holder>> {};
+// Specialization for always-supported unique_ptr holders:
+template <typename base, typename deleter>
+struct is_holder_type<base, std::unique_ptr<base, deleter>> : std::true_type {};
+
+template <typename T>
+struct handle_type_name {
+    static constexpr auto name = const_name<T>();
+};
+template <>
+struct handle_type_name<bool_> {
+    static constexpr auto name = const_name("bool");
+};
+template <>
+struct handle_type_name<bytes> {
+    static constexpr auto name = const_name(PYBIND11_BYTES_NAME);
+};
+template <>
+struct handle_type_name<int_> {
+    static constexpr auto name = const_name("int");
+};
+template <>
+struct handle_type_name<iterable> {
+    static constexpr auto name = const_name("Iterable");
+};
+template <>
+struct handle_type_name<iterator> {
+    static constexpr auto name = const_name("Iterator");
+};
+template <>
+struct handle_type_name<float_> {
+    static constexpr auto name = const_name("float");
+};
+template <>
+struct handle_type_name<none> {
+    static constexpr auto name = const_name("None");
+};
+template <>
+struct handle_type_name<args> {
+    static constexpr auto name = const_name("*args");
+};
+template <>
+struct handle_type_name<kwargs> {
+    static constexpr auto name = const_name("**kwargs");
+};
+
+template <typename type>
+struct pyobject_caster {
+    template <typename T = type, enable_if_t<std::is_same<T, handle>::value, int> = 0>
+    pyobject_caster() : value() {}
+
+    // `type` may not be default constructible (e.g. frozenset, anyset).  Initializing `value`
+    // to a nil handle is safe since it will only be accessed if `load` succeeds.
+    template <typename T = type, enable_if_t<std::is_base_of<object, T>::value, int> = 0>
+    pyobject_caster() : value(reinterpret_steal<type>(handle())) {}
+
+    template <typename T = type, enable_if_t<std::is_same<T, handle>::value, int> = 0>
+    bool load(handle src, bool /* convert */) {
+        value = src;
+        return static_cast<bool>(value);
+    }
+
+    template <typename T = type, enable_if_t<std::is_base_of<object, T>::value, int> = 0>
+    bool load(handle src, bool /* convert */) {
+        if (!isinstance<type>(src)) {
+            return false;
+        }
+        value = reinterpret_borrow<type>(src);
+        return true;
+    }
+
+    static handle cast(const handle &src, return_value_policy /* policy */, handle /* parent */) {
+        return src.inc_ref();
+    }
+    PYBIND11_TYPE_CASTER(type, handle_type_name<type>::name);
+};
+
+template <typename T>
+class type_caster<T, enable_if_t<is_pyobject<T>::value>> : public pyobject_caster<T> {};
+
+// Our conditions for enabling moving are quite restrictive:
+// At compile time:
+// - T needs to be a non-const, non-pointer, non-reference type
+// - type_caster<T>::operator T&() must exist
+// - the type must be move constructible (obviously)
+// At run-time:
+// - if the type is non-copy-constructible, the object must be the sole owner of the type (i.e. it
+//   must have ref_count() == 1)h
+// If any of the above are not satisfied, we fall back to copying.
+template <typename T>
+using move_is_plain_type
+    = satisfies_none_of<T, std::is_void, std::is_pointer, std::is_reference, std::is_const>;
+template <typename T, typename SFINAE = void>
+struct move_always : std::false_type {};
+template <typename T>
+struct move_always<
+    T,
+    enable_if_t<
+        all_of<move_is_plain_type<T>,
+               negation<is_copy_constructible<T>>,
+               std::is_move_constructible<T>,
+               std::is_same<decltype(std::declval<make_caster<T>>().operator T &()), T &>>::value>>
+    : std::true_type {};
+template <typename T, typename SFINAE = void>
+struct move_if_unreferenced : std::false_type {};
+template <typename T>
+struct move_if_unreferenced<
+    T,
+    enable_if_t<
+        all_of<move_is_plain_type<T>,
+               negation<move_always<T>>,
+               std::is_move_constructible<T>,
+               std::is_same<decltype(std::declval<make_caster<T>>().operator T &()), T &>>::value>>
+    : std::true_type {};
+template <typename T>
+using move_never = none_of<move_always<T>, move_if_unreferenced<T>>;
+
+// Detect whether returning a `type` from a cast on type's type_caster is going to result in a
+// reference or pointer to a local variable of the type_caster.  Basically, only
+// non-reference/pointer `type`s and reference/pointers from a type_caster_generic are safe;
+// everything else returns a reference/pointer to a local variable.
+template <typename type>
+using cast_is_temporary_value_reference
+    = bool_constant<(std::is_reference<type>::value || std::is_pointer<type>::value)
+                    && !std::is_base_of<type_caster_generic, make_caster<type>>::value
+                    && !std::is_same<intrinsic_t<type>, void>::value>;
+
+// When a value returned from a C++ function is being cast back to Python, we almost always want to
+// force `policy = move`, regardless of the return value policy the function/method was declared
+// with.
+template <typename Return, typename SFINAE = void>
+struct return_value_policy_override {
+    static return_value_policy policy(return_value_policy p) { return p; }
+};
+
+template <typename Return>
+struct return_value_policy_override<
+    Return,
+    detail::enable_if_t<std::is_base_of<type_caster_generic, make_caster<Return>>::value, void>> {
+    static return_value_policy policy(return_value_policy p) {
+        return !std::is_lvalue_reference<Return>::value && !std::is_pointer<Return>::value
+                   ? return_value_policy::move
+                   : p;
+    }
+};
+
+// Basic python -> C++ casting; throws if casting fails
+template <typename T, typename SFINAE>
+type_caster<T, SFINAE> &load_type(type_caster<T, SFINAE> &conv, const handle &handle) {
+    static_assert(!detail::is_pyobject<T>::value,
+                  "Internal error: type_caster should only be used for C++ types");
+    if (!conv.load(handle, true)) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+        throw cast_error("Unable to cast Python instance to C++ type (#define "
+                         "PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for details)");
+#else
+        throw cast_error("Unable to cast Python instance of type "
+                         + (std::string) str(type::handle_of(handle)) + " to C++ type '"
+                         + type_id<T>() + "'");
+#endif
+    }
+    return conv;
+}
+// Wrapper around the above that also constructs and returns a type_caster
+template <typename T>
+make_caster<T> load_type(const handle &handle) {
+    make_caster<T> conv;
+    load_type(conv, handle);
+    return conv;
+}
+
+PYBIND11_NAMESPACE_END(detail)
+
+// pytype -> C++ type
+template <typename T, detail::enable_if_t<!detail::is_pyobject<T>::value, int> = 0>
+T cast(const handle &handle) {
+    using namespace detail;
+    static_assert(!cast_is_temporary_value_reference<T>::value,
+                  "Unable to cast type to reference: value is local to type caster");
+    return cast_op<T>(load_type<T>(handle));
+}
+
+// pytype -> pytype (calls converting constructor)
+template <typename T, detail::enable_if_t<detail::is_pyobject<T>::value, int> = 0>
+T cast(const handle &handle) {
+    return T(reinterpret_borrow<object>(handle));
+}
+
+// C++ type -> py::object
+template <typename T, detail::enable_if_t<!detail::is_pyobject<T>::value, int> = 0>
+object cast(T &&value,
+            return_value_policy policy = return_value_policy::automatic_reference,
+            handle parent = handle()) {
+    using no_ref_T = typename std::remove_reference<T>::type;
+    if (policy == return_value_policy::automatic) {
+        policy = std::is_pointer<no_ref_T>::value     ? return_value_policy::take_ownership
+                 : std::is_lvalue_reference<T>::value ? return_value_policy::copy
+                                                      : return_value_policy::move;
+    } else if (policy == return_value_policy::automatic_reference) {
+        policy = std::is_pointer<no_ref_T>::value     ? return_value_policy::reference
+                 : std::is_lvalue_reference<T>::value ? return_value_policy::copy
+                                                      : return_value_policy::move;
+    }
+    return reinterpret_steal<object>(
+        detail::make_caster<T>::cast(std::forward<T>(value), policy, parent));
+}
+
+template <typename T>
+T handle::cast() const {
+    return pybind11::cast<T>(*this);
+}
+template <>
+inline void handle::cast() const {
+    return;
+}
+
+template <typename T>
+detail::enable_if_t<!detail::move_never<T>::value, T> move(object &&obj) {
+    if (obj.ref_count() > 1) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+        throw cast_error(
+            "Unable to cast Python instance to C++ rvalue: instance has multiple references"
+            " (#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for details)");
+#else
+        throw cast_error("Unable to move from Python " + (std::string) str(type::handle_of(obj))
+                         + " instance to C++ " + type_id<T>()
+                         + " instance: instance has multiple references");
+#endif
+    }
+
+    // Move into a temporary and return that, because the reference may be a local value of `conv`
+    T ret = std::move(detail::load_type<T>(obj).operator T &());
+    return ret;
+}
+
+// Calling cast() on an rvalue calls pybind11::cast with the object rvalue, which does:
+// - If we have to move (because T has no copy constructor), do it.  This will fail if the moved
+//   object has multiple references, but trying to copy will fail to compile.
+// - If both movable and copyable, check ref count: if 1, move; otherwise copy
+// - Otherwise (not movable), copy.
+template <typename T>
+detail::enable_if_t<!detail::is_pyobject<T>::value && detail::move_always<T>::value, T>
+cast(object &&object) {
+    return move<T>(std::move(object));
+}
+template <typename T>
+detail::enable_if_t<!detail::is_pyobject<T>::value && detail::move_if_unreferenced<T>::value, T>
+cast(object &&object) {
+    if (object.ref_count() > 1) {
+        return cast<T>(object);
+    }
+    return move<T>(std::move(object));
+}
+template <typename T>
+detail::enable_if_t<!detail::is_pyobject<T>::value && detail::move_never<T>::value, T>
+cast(object &&object) {
+    return cast<T>(object);
+}
+
+// pytype rvalue -> pytype (calls converting constructor)
+template <typename T>
+detail::enable_if_t<detail::is_pyobject<T>::value, T> cast(object &&object) {
+    return T(std::move(object));
+}
+
+template <typename T>
+T object::cast() const & {
+    return pybind11::cast<T>(*this);
+}
+template <typename T>
+T object::cast() && {
+    return pybind11::cast<T>(std::move(*this));
+}
+template <>
+inline void object::cast() const & {
+    return;
+}
+template <>
+inline void object::cast() && {
+    return;
+}
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+// Declared in pytypes.h:
+template <typename T, enable_if_t<!is_pyobject<T>::value, int>>
+object object_or_cast(T &&o) {
+    return pybind11::cast(std::forward<T>(o));
+}
+
+// Placeholder type for the unneeded (and dead code) static variable in the
+// PYBIND11_OVERRIDE_OVERRIDE macro
+struct override_unused {};
+template <typename ret_type>
+using override_caster_t = conditional_t<cast_is_temporary_value_reference<ret_type>::value,
+                                        make_caster<ret_type>,
+                                        override_unused>;
+
+// Trampoline use: for reference/pointer types to value-converted values, we do a value cast, then
+// store the result in the given variable.  For other types, this is a no-op.
+template <typename T>
+enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_ref(object &&o,
+                                                                     make_caster<T> &caster) {
+    return cast_op<T>(load_type(caster, o));
+}
+template <typename T>
+enable_if_t<!cast_is_temporary_value_reference<T>::value, T> cast_ref(object &&,
+                                                                      override_unused &) {
+    pybind11_fail("Internal error: cast_ref fallback invoked");
+}
+
+// Trampoline use: Having a pybind11::cast with an invalid reference type is going to
+// static_assert, even though if it's in dead code, so we provide a "trampoline" to pybind11::cast
+// that only does anything in cases where pybind11::cast is valid.
+template <typename T>
+enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_safe(object &&) {
+    pybind11_fail("Internal error: cast_safe fallback invoked");
+}
+template <typename T>
+enable_if_t<std::is_void<T>::value, void> cast_safe(object &&) {}
+template <typename T>
+enable_if_t<detail::none_of<cast_is_temporary_value_reference<T>, std::is_void<T>>::value, T>
+cast_safe(object &&o) {
+    return pybind11::cast<T>(std::move(o));
+}
+
+PYBIND11_NAMESPACE_END(detail)
+
+// The overloads could coexist, i.e. the #if is not strictly speaking needed,
+// but it is an easy minor optimization.
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+inline cast_error cast_error_unable_to_convert_call_arg() {
+    return cast_error("Unable to convert call argument to Python object (#define "
+                      "PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for details)");
+}
+#else
+inline cast_error cast_error_unable_to_convert_call_arg(const std::string &name,
+                                                        const std::string &type) {
+    return cast_error("Unable to convert call argument '" + name + "' of type '" + type
+                      + "' to Python object");
+}
+#endif
+
+template <return_value_policy policy = return_value_policy::automatic_reference>
+tuple make_tuple() {
+    return tuple(0);
+}
+
+template <return_value_policy policy = return_value_policy::automatic_reference, typename... Args>
+tuple make_tuple(Args &&...args_) {
+    constexpr size_t size = sizeof...(Args);
+    std::array<object, size> args{{reinterpret_steal<object>(
+        detail::make_caster<Args>::cast(std::forward<Args>(args_), policy, nullptr))...}};
+    for (size_t i = 0; i < args.size(); i++) {
+        if (!args[i]) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+            throw cast_error_unable_to_convert_call_arg();
+#else
+            std::array<std::string, size> argtypes{{type_id<Args>()...}};
+            throw cast_error_unable_to_convert_call_arg(std::to_string(i), argtypes[i]);
+#endif
+        }
+    }
+    tuple result(size);
+    int counter = 0;
+    for (auto &arg_value : args) {
+        PyTuple_SET_ITEM(result.ptr(), counter++, arg_value.release().ptr());
+    }
+    return result;
+}
+
+/// \ingroup annotations
+/// Annotation for arguments
+struct arg {
+    /// Constructs an argument with the name of the argument; if null or omitted, this is a
+    /// positional argument.
+    constexpr explicit arg(const char *name = nullptr)
+        : name(name), flag_noconvert(false), flag_none(true) {}
+    /// Assign a value to this argument
+    template <typename T>
+    arg_v operator=(T &&value) const;
+    /// Indicate that the type should not be converted in the type caster
+    arg &noconvert(bool flag = true) {
+        flag_noconvert = flag;
+        return *this;
+    }
+    /// Indicates that the argument should/shouldn't allow None (e.g. for nullable pointer args)
+    arg &none(bool flag = true) {
+        flag_none = flag;
+        return *this;
+    }
+
+    const char *name;        ///< If non-null, this is a named kwargs argument
+    bool flag_noconvert : 1; ///< If set, do not allow conversion (requires a supporting type
+                             ///< caster!)
+    bool flag_none : 1;      ///< If set (the default), allow None to be passed to this argument
+};
+
+/// \ingroup annotations
+/// Annotation for arguments with values
+struct arg_v : arg {
+private:
+    template <typename T>
+    arg_v(arg &&base, T &&x, const char *descr = nullptr)
+        : arg(base), value(reinterpret_steal<object>(detail::make_caster<T>::cast(
+                         std::forward<T>(x), return_value_policy::automatic, {}))),
+          descr(descr)
+#if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+          ,
+          type(type_id<T>())
+#endif
+    {
+        // Workaround! See:
+        // https://github.com/pybind/pybind11/issues/2336
+        // https://github.com/pybind/pybind11/pull/2685#issuecomment-731286700
+        if (PyErr_Occurred()) {
+            PyErr_Clear();
+        }
+    }
+
+public:
+    /// Direct construction with name, default, and description
+    template <typename T>
+    arg_v(const char *name, T &&x, const char *descr = nullptr)
+        : arg_v(arg(name), std::forward<T>(x), descr) {}
+
+    /// Called internally when invoking `py::arg("a") = value`
+    template <typename T>
+    arg_v(const arg &base, T &&x, const char *descr = nullptr)
+        : arg_v(arg(base), std::forward<T>(x), descr) {}
+
+    /// Same as `arg::noconvert()`, but returns *this as arg_v&, not arg&
+    arg_v &noconvert(bool flag = true) {
+        arg::noconvert(flag);
+        return *this;
+    }
+
+    /// Same as `arg::nonone()`, but returns *this as arg_v&, not arg&
+    arg_v &none(bool flag = true) {
+        arg::none(flag);
+        return *this;
+    }
+
+    /// The default value
+    object value;
+    /// The (optional) description of the default value
+    const char *descr;
+#if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+    /// The C++ type name of the default value (only available when compiled in debug mode)
+    std::string type;
+#endif
+};
+
+/// \ingroup annotations
+/// Annotation indicating that all following arguments are keyword-only; the is the equivalent of
+/// an unnamed '*' argument
+struct kw_only {};
+
+/// \ingroup annotations
+/// Annotation indicating that all previous arguments are positional-only; the is the equivalent of
+/// an unnamed '/' argument (in Python 3.8)
+struct pos_only {};
+
+template <typename T>
+arg_v arg::operator=(T &&value) const {
+    return {*this, std::forward<T>(value)};
+}
+
+/// Alias for backward compatibility -- to be removed in version 2.0
+template <typename /*unused*/>
+using arg_t = arg_v;
+
+inline namespace literals {
+/** \rst
+    String literal version of `arg`
+ \endrst */
+constexpr arg operator"" _a(const char *name, size_t) { return arg(name); }
+} // namespace literals
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+template <typename T>
+using is_kw_only = std::is_same<intrinsic_t<T>, kw_only>;
+template <typename T>
+using is_pos_only = std::is_same<intrinsic_t<T>, pos_only>;
+
+// forward declaration (definition in attr.h)
+struct function_record;
+
+/// Internal data associated with a single function call
+struct function_call {
+    function_call(const function_record &f, handle p); // Implementation in attr.h
+
+    /// The function data:
+    const function_record &func;
+
+    /// Arguments passed to the function:
+    std::vector<handle> args;
+
+    /// The `convert` value the arguments should be loaded with
+    std::vector<bool> args_convert;
+
+    /// Extra references for the optional `py::args` and/or `py::kwargs` arguments (which, if
+    /// present, are also in `args` but without a reference).
+    object args_ref, kwargs_ref;
+
+    /// The parent, if any
+    handle parent;
+
+    /// If this is a call to an initializer, this argument contains `self`
+    handle init_self;
+};
+
+/// Helper class which loads arguments for C++ functions called from Python
+template <typename... Args>
+class argument_loader {
+    using indices = make_index_sequence<sizeof...(Args)>;
+
+    template <typename Arg>
+    using argument_is_args = std::is_same<intrinsic_t<Arg>, args>;
+    template <typename Arg>
+    using argument_is_kwargs = std::is_same<intrinsic_t<Arg>, kwargs>;
+    // Get kwargs argument position, or -1 if not present:
+    static constexpr auto kwargs_pos = constexpr_last<argument_is_kwargs, Args...>();
+
+    static_assert(kwargs_pos == -1 || kwargs_pos == (int) sizeof...(Args) - 1,
+                  "py::kwargs is only permitted as the last argument of a function");
+
+public:
+    static constexpr bool has_kwargs = kwargs_pos != -1;
+
+    // py::args argument position; -1 if not present.
+    static constexpr int args_pos = constexpr_last<argument_is_args, Args...>();
+
+    static_assert(args_pos == -1 || args_pos == constexpr_first<argument_is_args, Args...>(),
+                  "py::args cannot be specified more than once");
+
+    static constexpr auto arg_names = concat(type_descr(make_caster<Args>::name)...);
+
+    bool load_args(function_call &call) { return load_impl_sequence(call, indices{}); }
+
+    template <typename Return, typename Guard, typename Func>
+    // NOLINTNEXTLINE(readability-const-return-type)
+    enable_if_t<!std::is_void<Return>::value, Return> call(Func &&f) && {
+        return std::move(*this).template call_impl<remove_cv_t<Return>>(
+            std::forward<Func>(f), indices{}, Guard{});
+    }
+
+    template <typename Return, typename Guard, typename Func>
+    enable_if_t<std::is_void<Return>::value, void_type> call(Func &&f) && {
+        std::move(*this).template call_impl<remove_cv_t<Return>>(
+            std::forward<Func>(f), indices{}, Guard{});
+        return void_type();
+    }
+
+private:
+    static bool load_impl_sequence(function_call &, index_sequence<>) { return true; }
+
+    template <size_t... Is>
+    bool load_impl_sequence(function_call &call, index_sequence<Is...>) {
+#ifdef __cpp_fold_expressions
+        if ((... || !std::get<Is>(argcasters).load(call.args[Is], call.args_convert[Is]))) {
+            return false;
+        }
+#else
+        for (bool r : {std::get<Is>(argcasters).load(call.args[Is], call.args_convert[Is])...}) {
+            if (!r) {
+                return false;
+            }
+        }
+#endif
+        return true;
+    }
+
+    template <typename Return, typename Func, size_t... Is, typename Guard>
+    Return call_impl(Func &&f, index_sequence<Is...>, Guard &&) && {
+        return std::forward<Func>(f)(cast_op<Args>(std::move(std::get<Is>(argcasters)))...);
+    }
+
+    std::tuple<make_caster<Args>...> argcasters;
+};
+
+/// Helper class which collects only positional arguments for a Python function call.
+/// A fancier version below can collect any argument, but this one is optimal for simple calls.
+template <return_value_policy policy>
+class simple_collector {
+public:
+    template <typename... Ts>
+    explicit simple_collector(Ts &&...values)
+        : m_args(pybind11::make_tuple<policy>(std::forward<Ts>(values)...)) {}
+
+    const tuple &args() const & { return m_args; }
+    dict kwargs() const { return {}; }
+
+    tuple args() && { return std::move(m_args); }
+
+    /// Call a Python function and pass the collected arguments
+    object call(PyObject *ptr) const {
+        PyObject *result = PyObject_CallObject(ptr, m_args.ptr());
+        if (!result) {
+            throw error_already_set();
+        }
+        return reinterpret_steal<object>(result);
+    }
+
+private:
+    tuple m_args;
+};
+
+/// Helper class which collects positional, keyword, * and ** arguments for a Python function call
+template <return_value_policy policy>
+class unpacking_collector {
+public:
+    template <typename... Ts>
+    explicit unpacking_collector(Ts &&...values) {
+        // Tuples aren't (easily) resizable so a list is needed for collection,
+        // but the actual function call strictly requires a tuple.
+        auto args_list = list();
+        using expander = int[];
+        (void) expander{0, (process(args_list, std::forward<Ts>(values)), 0)...};
+
+        m_args = std::move(args_list);
+    }
+
+    const tuple &args() const & { return m_args; }
+    const dict &kwargs() const & { return m_kwargs; }
+
+    tuple args() && { return std::move(m_args); }
+    dict kwargs() && { return std::move(m_kwargs); }
+
+    /// Call a Python function and pass the collected arguments
+    object call(PyObject *ptr) const {
+        PyObject *result = PyObject_Call(ptr, m_args.ptr(), m_kwargs.ptr());
+        if (!result) {
+            throw error_already_set();
+        }
+        return reinterpret_steal<object>(result);
+    }
+
+private:
+    template <typename T>
+    void process(list &args_list, T &&x) {
+        auto o = reinterpret_steal<object>(
+            detail::make_caster<T>::cast(std::forward<T>(x), policy, {}));
+        if (!o) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+            throw cast_error_unable_to_convert_call_arg();
+#else
+            throw cast_error_unable_to_convert_call_arg(std::to_string(args_list.size()),
+                                                        type_id<T>());
+#endif
+        }
+        args_list.append(std::move(o));
+    }
+
+    void process(list &args_list, detail::args_proxy ap) {
+        for (auto a : ap) {
+            args_list.append(a);
+        }
+    }
+
+    void process(list & /*args_list*/, arg_v a) {
+        if (!a.name) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+            nameless_argument_error();
+#else
+            nameless_argument_error(a.type);
+#endif
+        }
+        if (m_kwargs.contains(a.name)) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+            multiple_values_error();
+#else
+            multiple_values_error(a.name);
+#endif
+        }
+        if (!a.value) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+            throw cast_error_unable_to_convert_call_arg();
+#else
+            throw cast_error_unable_to_convert_call_arg(a.name, a.type);
+#endif
+        }
+        m_kwargs[a.name] = std::move(a.value);
+    }
+
+    void process(list & /*args_list*/, detail::kwargs_proxy kp) {
+        if (!kp) {
+            return;
+        }
+        for (auto k : reinterpret_borrow<dict>(kp)) {
+            if (m_kwargs.contains(k.first)) {
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+                multiple_values_error();
+#else
+                multiple_values_error(str(k.first));
+#endif
+            }
+            m_kwargs[k.first] = k.second;
+        }
+    }
+
+    [[noreturn]] static void nameless_argument_error() {
+        throw type_error(
+            "Got kwargs without a name; only named arguments "
+            "may be passed via py::arg() to a python function call. "
+            "(#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for details)");
+    }
+    [[noreturn]] static void nameless_argument_error(const std::string &type) {
+        throw type_error("Got kwargs without a name of type '" + type
+                         + "'; only named "
+                           "arguments may be passed via py::arg() to a python function call. ");
+    }
+    [[noreturn]] static void multiple_values_error() {
+        throw type_error(
+            "Got multiple values for keyword argument "
+            "(#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for details)");
+    }
+
+    [[noreturn]] static void multiple_values_error(const std::string &name) {
+        throw type_error("Got multiple values for keyword argument '" + name + "'");
+    }
+
+private:
+    tuple m_args;
+    dict m_kwargs;
+};
+
+// [workaround(intel)] Separate function required here
+// We need to put this into a separate function because the Intel compiler
+// fails to compile enable_if_t<!all_of<is_positional<Args>...>::value>
+// (tested with ICC 2021.1 Beta 20200827).
+template <typename... Args>
+constexpr bool args_are_all_positional() {
+    return all_of<is_positional<Args>...>::value;
+}
+
+/// Collect only positional arguments for a Python function call
+template <return_value_policy policy,
+          typename... Args,
+          typename = enable_if_t<args_are_all_positional<Args...>()>>
+simple_collector<policy> collect_arguments(Args &&...args) {
+    return simple_collector<policy>(std::forward<Args>(args)...);
+}
+
+/// Collect all arguments, including keywords and unpacking (only instantiated when needed)
+template <return_value_policy policy,
+          typename... Args,
+          typename = enable_if_t<!args_are_all_positional<Args...>()>>
+unpacking_collector<policy> collect_arguments(Args &&...args) {
+    // Following argument order rules for generalized unpacking according to PEP 448
+    static_assert(constexpr_last<is_positional, Args...>()
+                          < constexpr_first<is_keyword_or_ds, Args...>()
+                      && constexpr_last<is_s_unpacking, Args...>()
+                             < constexpr_first<is_ds_unpacking, Args...>(),
+                  "Invalid function call: positional args must precede keywords and ** unpacking; "
+                  "* unpacking must precede ** unpacking");
+    return unpacking_collector<policy>(std::forward<Args>(args)...);
+}
+
+template <typename Derived>
+template <return_value_policy policy, typename... Args>
+object object_api<Derived>::operator()(Args &&...args) const {
+#ifndef NDEBUG
+    if (!PyGILState_Check()) {
+        pybind11_fail("pybind11::object_api<>::operator() PyGILState_Check() failure.");
+    }
+#endif
+    return detail::collect_arguments<policy>(std::forward<Args>(args)...).call(derived().ptr());
+}
+
+template <typename Derived>
+template <return_value_policy policy, typename... Args>
+object object_api<Derived>::call(Args &&...args) const {
+    return operator()<policy>(std::forward<Args>(args)...);
+}
+
+PYBIND11_NAMESPACE_END(detail)
+
+template <typename T>
+handle type::handle_of() {
+    static_assert(std::is_base_of<detail::type_caster_generic, detail::make_caster<T>>::value,
+                  "py::type::of<T> only supports the case where T is a registered C++ types.");
+
+    return detail::get_type_handle(typeid(T), true);
+}
+
+#define PYBIND11_MAKE_OPAQUE(...)                                                                 \
+    PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)                                                  \
+    namespace detail {                                                                            \
+    template <>                                                                                   \
+    class type_caster<__VA_ARGS__> : public type_caster_base<__VA_ARGS__> {};                     \
+    }                                                                                             \
+    PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
+
+/// Lets you pass a type containing a `,` through a macro parameter without needing a separate
+/// typedef, e.g.:
+/// `PYBIND11_OVERRIDE(PYBIND11_TYPE(ReturnType<A, B>), PYBIND11_TYPE(Parent<C, D>), f, arg)`
+#define PYBIND11_TYPE(...) __VA_ARGS__
+
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/Patches/pybind11/detail/class.h b/Patches/pybind11/detail/class.h
new file mode 100644
index 00000000..8ebbdd7c
--- /dev/null
+++ b/Patches/pybind11/detail/class.h
@@ -0,0 +1,737 @@
+/*
+    pybind11/detail/class.h: Python C API implementation details for py::class_
+
+    Copyright (c) 2017 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#pragma once
+
+#include "../attr.h"
+#include "../options.h"
+
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+#if !defined(PYPY_VERSION)
+#    define PYBIND11_BUILTIN_QUALNAME
+#    define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj)
+#else
+// In PyPy, we still set __qualname__ so that we can produce reliable function type
+// signatures; in CPython this macro expands to nothing:
+#    define PYBIND11_SET_OLDPY_QUALNAME(obj, nameobj)                                             \
+        setattr((PyObject *) obj, "__qualname__", nameobj)
+#endif
+
+inline std::string get_fully_qualified_tp_name(PyTypeObject *type) {
+#if !defined(PYPY_VERSION)
+    return type->tp_name;
+#else
+    auto module_name = handle((PyObject *) type).attr("__module__").cast<std::string>();
+    if (module_name == PYBIND11_BUILTINS_MODULE)
+        return type->tp_name;
+    else
+        return std::move(module_name) + "." + type->tp_name;
+#endif
+}
+
+inline PyTypeObject *type_incref(PyTypeObject *type) {
+    Py_INCREF(type);
+    return type;
+}
+
+#if !defined(PYPY_VERSION)
+
+/// `pybind11_static_property.__get__()`: Always pass the class instead of the instance.
+extern "C" inline PyObject *pybind11_static_get(PyObject *self, PyObject * /*ob*/, PyObject *cls) {
+    return PyProperty_Type.tp_descr_get(self, cls, cls);
+}
+
+/// `pybind11_static_property.__set__()`: Just like the above `__get__()`.
+extern "C" inline int pybind11_static_set(PyObject *self, PyObject *obj, PyObject *value) {
+    PyObject *cls = PyType_Check(obj) ? obj : (PyObject *) Py_TYPE(obj);
+    return PyProperty_Type.tp_descr_set(self, cls, value);
+}
+
+// Forward declaration to use in `make_static_property_type()`
+inline void enable_dynamic_attributes(PyHeapTypeObject *heap_type);
+
+/** A `static_property` is the same as a `property` but the `__get__()` and `__set__()`
+    methods are modified to always use the object type instead of a concrete instance.
+    Return value: New reference. */
+inline PyTypeObject *make_static_property_type() {
+    constexpr auto *name = "pybind11_static_property";
+    auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name));
+
+    /* Danger zone: from now (and until PyType_Ready), make sure to
+       issue no Python C API calls which could potentially invoke the
+       garbage collector (the GC will call type_traverse(), which will in
+       turn find the newly constructed type in an invalid state) */
+    auto *heap_type = (PyHeapTypeObject *) PyType_Type.tp_alloc(&PyType_Type, 0);
+    if (!heap_type) {
+        pybind11_fail("make_static_property_type(): error allocating type!");
+    }
+
+    heap_type->ht_name = name_obj.inc_ref().ptr();
+#    ifdef PYBIND11_BUILTIN_QUALNAME
+    heap_type->ht_qualname = name_obj.inc_ref().ptr();
+#    endif
+
+    auto *type = &heap_type->ht_type;
+    type->tp_name = name;
+    type->tp_base = type_incref(&PyProperty_Type);
+    type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
+    type->tp_descr_get = pybind11_static_get;
+    type->tp_descr_set = pybind11_static_set;
+
+    if (PyType_Ready(type) < 0) {
+        pybind11_fail("make_static_property_type(): failure in PyType_Ready()!");
+    }
+
+#    if PY_VERSION_HEX >= 0x030C0000
+    // PRE 3.12 FEATURE FREEZE. PLEASE REVIEW AFTER FREEZE.
+    // Since Python-3.12 property-derived types are required to
+    // have dynamic attributes (to set `__doc__`)
+    enable_dynamic_attributes(heap_type);
+#    endif
+
+    setattr((PyObject *) type, "__module__", str("pybind11_builtins"));
+    PYBIND11_SET_OLDPY_QUALNAME(type, name_obj);
+
+    return type;
+}
+
+#else // PYPY
+
+/** PyPy has some issues with the above C API, so we evaluate Python code instead.
+    This function will only be called once so performance isn't really a concern.
+    Return value: New reference. */
+inline PyTypeObject *make_static_property_type() {
+    auto d = dict();
+    PyObject *result = PyRun_String(R"(\
+class pybind11_static_property(property):
+    def __get__(self, obj, cls):
+        return property.__get__(self, cls, cls)
+
+    def __set__(self, obj, value):
+        cls = obj if isinstance(obj, type) else type(obj)
+        property.__set__(self, cls, value)
+)",
+                                    Py_file_input,
+                                    d.ptr(),
+                                    d.ptr());
+    if (result == nullptr)
+        throw error_already_set();
+    Py_DECREF(result);
+    return (PyTypeObject *) d["pybind11_static_property"].cast<object>().release().ptr();
+}
+
+#endif // PYPY
+
+/** Types with static properties need to handle `Type.static_prop = x` in a specific way.
+    By default, Python replaces the `static_property` itself, but for wrapped C++ types
+    we need to call `static_property.__set__()` in order to propagate the new value to
+    the underlying C++ data structure. */
+extern "C" inline int pybind11_meta_setattro(PyObject *obj, PyObject *name, PyObject *value) {
+    // Use `_PyType_Lookup()` instead of `PyObject_GetAttr()` in order to get the raw
+    // descriptor (`property`) instead of calling `tp_descr_get` (`property.__get__()`).
+    PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name);
+
+    // The following assignment combinations are possible:
+    //   1. `Type.static_prop = value`             --> descr_set: `Type.static_prop.__set__(value)`
+    //   2. `Type.static_prop = other_static_prop` --> setattro:  replace existing `static_prop`
+    //   3. `Type.regular_attribute = value`       --> setattro:  regular attribute assignment
+    auto *const static_prop = (PyObject *) get_internals().static_property_type;
+    const auto call_descr_set = (descr != nullptr) && (value != nullptr)
+                                && (PyObject_IsInstance(descr, static_prop) != 0)
+                                && (PyObject_IsInstance(value, static_prop) == 0);
+    if (call_descr_set) {
+        // Call `static_property.__set__()` instead of replacing the `static_property`.
+#if !defined(PYPY_VERSION)
+        return Py_TYPE(descr)->tp_descr_set(descr, obj, value);
+#else
+        if (PyObject *result = PyObject_CallMethod(descr, "__set__", "OO", obj, value)) {
+            Py_DECREF(result);
+            return 0;
+        } else {
+            return -1;
+        }
+#endif
+    } else {
+        // Replace existing attribute.
+        return PyType_Type.tp_setattro(obj, name, value);
+    }
+}
+
+/**
+ * Python 3's PyInstanceMethod_Type hides itself via its tp_descr_get, which prevents aliasing
+ * methods via cls.attr("m2") = cls.attr("m1"): instead the tp_descr_get returns a plain function,
+ * when called on a class, or a PyMethod, when called on an instance.  Override that behaviour here
+ * to do a special case bypass for PyInstanceMethod_Types.
+ */
+extern "C" inline PyObject *pybind11_meta_getattro(PyObject *obj, PyObject *name) {
+    PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name);
+    if (descr && PyInstanceMethod_Check(descr)) {
+        Py_INCREF(descr);
+        return descr;
+    }
+    return PyType_Type.tp_getattro(obj, name);
+}
+
+/// metaclass `__call__` function that is used to create all pybind11 objects.
+extern "C" inline PyObject *pybind11_meta_call(PyObject *type, PyObject *args, PyObject *kwargs) {
+
+    // use the default metaclass call to create/initialize the object
+    PyObject *self = PyType_Type.tp_call(type, args, kwargs);
+    if (self == nullptr) {
+        return nullptr;
+    }
+
+    // This must be a pybind11 instance
+    auto *instance = reinterpret_cast<detail::instance *>(self);
+    // Mark this instance as an instance of an alias class
+    instance->is_alias = instance->has_alias;
+
+    // Ensure that the base __init__ function(s) were called
+    for (const auto &vh : values_and_holders(instance)) {
+        if (!vh.holder_constructed()) {
+            PyErr_Format(PyExc_TypeError,
+                         "%.200s.__init__() must be called when overriding __init__",
+                         get_fully_qualified_tp_name(vh.type->type).c_str());
+            Py_DECREF(self);
+            return nullptr;
+        }
+    }
+
+    return self;
+}
+
+/// Cleanup the type-info for a pybind11-registered type.
+extern "C" inline void pybind11_meta_dealloc(PyObject *obj) {
+    auto *type = (PyTypeObject *) obj;
+    auto &internals = get_internals();
+
+    // A pybind11-registered type will:
+    // 1) be found in internals.registered_types_py
+    // 2) have exactly one associated `detail::type_info`
+    auto found_type = internals.registered_types_py.find(type);
+    if (found_type != internals.registered_types_py.end() && found_type->second.size() == 1
+        && found_type->second[0]->type == type) {
+
+        auto *tinfo = found_type->second[0];
+        auto tindex = std::type_index(*tinfo->cpptype);
+        internals.direct_conversions.erase(tindex);
+
+        if (tinfo->module_local) {
+            get_local_internals().registered_types_cpp.erase(tindex);
+        } else {
+            internals.registered_types_cpp.erase(tindex);
+        }
+        internals.registered_types_py.erase(tinfo->type);
+
+        // Actually just `std::erase_if`, but that's only available in C++20
+        auto &cache = internals.inactive_override_cache;
+        for (auto it = cache.begin(), last = cache.end(); it != last;) {
+            if (it->first == (PyObject *) tinfo->type) {
+                it = cache.erase(it);
+            } else {
+                ++it;
+            }
+        }
+
+        delete tinfo;
+    }
+
+    PyType_Type.tp_dealloc(obj);
+}
+
+/** This metaclass is assigned by default to all pybind11 types and is required in order
+    for static properties to function correctly. Users may override this using `py::metaclass`.
+    Return value: New reference. */
+inline PyTypeObject *make_default_metaclass() {
+    constexpr auto *name = "pybind11_type";
+    auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name));
+
+    /* Danger zone: from now (and until PyType_Ready), make sure to
+       issue no Python C API calls which could potentially invoke the
+       garbage collector (the GC will call type_traverse(), which will in
+       turn find the newly constructed type in an invalid state) */
+    auto *heap_type = (PyHeapTypeObject *) PyType_Type.tp_alloc(&PyType_Type, 0);
+    if (!heap_type) {
+        pybind11_fail("make_default_metaclass(): error allocating metaclass!");
+    }
+
+    heap_type->ht_name = name_obj.inc_ref().ptr();
+#ifdef PYBIND11_BUILTIN_QUALNAME
+    heap_type->ht_qualname = name_obj.inc_ref().ptr();
+#endif
+
+    auto *type = &heap_type->ht_type;
+    type->tp_name = name;
+    type->tp_base = type_incref(&PyType_Type);
+    type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
+
+    type->tp_call = pybind11_meta_call;
+
+    type->tp_setattro = pybind11_meta_setattro;
+    type->tp_getattro = pybind11_meta_getattro;
+
+    type->tp_dealloc = pybind11_meta_dealloc;
+
+    if (PyType_Ready(type) < 0) {
+        pybind11_fail("make_default_metaclass(): failure in PyType_Ready()!");
+    }
+
+    setattr((PyObject *) type, "__module__", str("pybind11_builtins"));
+    PYBIND11_SET_OLDPY_QUALNAME(type, name_obj);
+
+    return type;
+}
+
+/// For multiple inheritance types we need to recursively register/deregister base pointers for any
+/// base classes with pointers that are difference from the instance value pointer so that we can
+/// correctly recognize an offset base class pointer. This calls a function with any offset base
+/// ptrs.
+inline void traverse_offset_bases(void *valueptr,
+                                  const detail::type_info *tinfo,
+                                  instance *self,
+                                  bool (*f)(void * /*parentptr*/, instance * /*self*/)) {
+    for (handle h : reinterpret_borrow<tuple>(tinfo->type->tp_bases)) {
+        if (auto *parent_tinfo = get_type_info((PyTypeObject *) h.ptr())) {
+            for (auto &c : parent_tinfo->implicit_casts) {
+                if (c.first == tinfo->cpptype) {
+                    auto *parentptr = c.second(valueptr);
+                    if (parentptr != valueptr) {
+                        f(parentptr, self);
+                    }
+                    traverse_offset_bases(parentptr, parent_tinfo, self, f);
+                    break;
+                }
+            }
+        }
+    }
+}
+
+inline bool register_instance_impl(void *ptr, instance *self) {
+    get_internals().registered_instances.emplace(ptr, self);
+    return true; // unused, but gives the same signature as the deregister func
+}
+inline bool deregister_instance_impl(void *ptr, instance *self) {
+    auto &registered_instances = get_internals().registered_instances;
+    auto range = registered_instances.equal_range(ptr);
+    for (auto it = range.first; it != range.second; ++it) {
+        if (self == it->second) {
+            registered_instances.erase(it);
+            return true;
+        }
+    }
+    return false;
+}
+
+inline void register_instance(instance *self, void *valptr, const type_info *tinfo) {
+    register_instance_impl(valptr, self);
+    if (!tinfo->simple_ancestors) {
+        traverse_offset_bases(valptr, tinfo, self, register_instance_impl);
+    }
+}
+
+inline bool deregister_instance(instance *self, void *valptr, const type_info *tinfo) {
+    bool ret = deregister_instance_impl(valptr, self);
+    if (!tinfo->simple_ancestors) {
+        traverse_offset_bases(valptr, tinfo, self, deregister_instance_impl);
+    }
+    return ret;
+}
+
+/// Instance creation function for all pybind11 types. It allocates the internal instance layout
+/// for holding C++ objects and holders.  Allocation is done lazily (the first time the instance is
+/// cast to a reference or pointer), and initialization is done by an `__init__` function.
+inline PyObject *make_new_instance(PyTypeObject *type) {
+#if defined(PYPY_VERSION)
+    // PyPy gets tp_basicsize wrong (issue 2482) under multiple inheritance when the first
+    // inherited object is a plain Python type (i.e. not derived from an extension type).  Fix it.
+    ssize_t instance_size = static_cast<ssize_t>(sizeof(instance));
+    if (type->tp_basicsize < instance_size) {
+        type->tp_basicsize = instance_size;
+    }
+#endif
+    PyObject *self = type->tp_alloc(type, 0);
+    auto *inst = reinterpret_cast<instance *>(self);
+    // Allocate the value/holder internals:
+    inst->allocate_layout();
+
+    return self;
+}
+
+/// Instance creation function for all pybind11 types. It only allocates space for the
+/// C++ object, but doesn't call the constructor -- an `__init__` function must do that.
+extern "C" inline PyObject *pybind11_object_new(PyTypeObject *type, PyObject *, PyObject *) {
+    return make_new_instance(type);
+}
+
+/// An `__init__` function constructs the C++ object. Users should provide at least one
+/// of these using `py::init` or directly with `.def(__init__, ...)`. Otherwise, the
+/// following default function will be used which simply throws an exception.
+extern "C" inline int pybind11_object_init(PyObject *self, PyObject *, PyObject *) {
+    PyTypeObject *type = Py_TYPE(self);
+    std::string msg = get_fully_qualified_tp_name(type) + ": No constructor defined!";
+    PyErr_SetString(PyExc_TypeError, msg.c_str());
+    return -1;
+}
+
+inline void add_patient(PyObject *nurse, PyObject *patient) {
+    auto &internals = get_internals();
+    auto *instance = reinterpret_cast<detail::instance *>(nurse);
+    instance->has_patients = true;
+    Py_INCREF(patient);
+    internals.patients[nurse].push_back(patient);
+}
+
+inline void clear_patients(PyObject *self) {
+    auto *instance = reinterpret_cast<detail::instance *>(self);
+    auto &internals = get_internals();
+    auto pos = internals.patients.find(self);
+    assert(pos != internals.patients.end());
+    // Clearing the patients can cause more Python code to run, which
+    // can invalidate the iterator. Extract the vector of patients
+    // from the unordered_map first.
+    auto patients = std::move(pos->second);
+    internals.patients.erase(pos);
+    instance->has_patients = false;
+    for (PyObject *&patient : patients) {
+        Py_CLEAR(patient);
+    }
+}
+
+/// Clears all internal data from the instance and removes it from registered instances in
+/// preparation for deallocation.
+inline void clear_instance(PyObject *self) {
+    auto *instance = reinterpret_cast<detail::instance *>(self);
+
+    // Deallocate any values/holders, if present:
+    for (auto &v_h : values_and_holders(instance)) {
+        if (v_h) {
+
+            // We have to deregister before we call dealloc because, for virtual MI types, we still
+            // need to be able to get the parent pointers.
+            if (v_h.instance_registered()
+                && !deregister_instance(instance, v_h.value_ptr(), v_h.type)) {
+                pybind11_fail(
+                    "pybind11_object_dealloc(): Tried to deallocate unregistered instance!");
+            }
+
+            if (instance->owned || v_h.holder_constructed()) {
+                v_h.type->dealloc(v_h);
+            }
+        }
+    }
+    // Deallocate the value/holder layout internals:
+    instance->deallocate_layout();
+
+    if (instance->weakrefs) {
+        PyObject_ClearWeakRefs(self);
+    }
+
+    PyObject **dict_ptr = _PyObject_GetDictPtr(self);
+    if (dict_ptr) {
+        Py_CLEAR(*dict_ptr);
+    }
+
+    if (instance->has_patients) {
+        clear_patients(self);
+    }
+}
+
+/// Instance destructor function for all pybind11 types. It calls `type_info.dealloc`
+/// to destroy the C++ object itself, while the rest is Python bookkeeping.
+extern "C" inline void pybind11_object_dealloc(PyObject *self) {
+    clear_instance(self);
+
+    auto *type = Py_TYPE(self);
+    type->tp_free(self);
+
+#if PY_VERSION_HEX < 0x03080000
+    // `type->tp_dealloc != pybind11_object_dealloc` means that we're being called
+    // as part of a derived type's dealloc, in which case we're not allowed to decref
+    // the type here. For cross-module compatibility, we shouldn't compare directly
+    // with `pybind11_object_dealloc`, but with the common one stashed in internals.
+    auto pybind11_object_type = (PyTypeObject *) get_internals().instance_base;
+    if (type->tp_dealloc == pybind11_object_type->tp_dealloc)
+        Py_DECREF(type);
+#else
+    // This was not needed before Python 3.8 (Python issue 35810)
+    // https://github.com/pybind/pybind11/issues/1946
+    Py_DECREF(type);
+#endif
+}
+
+std::string error_string();
+
+/** Create the type which can be used as a common base for all classes.  This is
+    needed in order to satisfy Python's requirements for multiple inheritance.
+    Return value: New reference. */
+inline PyObject *make_object_base_type(PyTypeObject *metaclass) {
+    constexpr auto *name = "pybind11_object";
+    auto name_obj = reinterpret_steal<object>(PYBIND11_FROM_STRING(name));
+
+    /* Danger zone: from now (and until PyType_Ready), make sure to
+       issue no Python C API calls which could potentially invoke the
+       garbage collector (the GC will call type_traverse(), which will in
+       turn find the newly constructed type in an invalid state) */
+    auto *heap_type = (PyHeapTypeObject *) metaclass->tp_alloc(metaclass, 0);
+    if (!heap_type) {
+        pybind11_fail("make_object_base_type(): error allocating type!");
+    }
+
+    heap_type->ht_name = name_obj.inc_ref().ptr();
+#ifdef PYBIND11_BUILTIN_QUALNAME
+    heap_type->ht_qualname = name_obj.inc_ref().ptr();
+#endif
+
+    auto *type = &heap_type->ht_type;
+    type->tp_name = name;
+    type->tp_base = type_incref(&PyBaseObject_Type);
+    type->tp_basicsize = static_cast<ssize_t>(sizeof(instance));
+    type->tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
+
+    type->tp_new = pybind11_object_new;
+    type->tp_init = pybind11_object_init;
+    type->tp_dealloc = pybind11_object_dealloc;
+
+    /* Support weak references (needed for the keep_alive feature) */
+    type->tp_weaklistoffset = offsetof(instance, weakrefs);
+
+    if (PyType_Ready(type) < 0) {
+        pybind11_fail("PyType_Ready failed in make_object_base_type(): " + error_string());
+    }
+
+    setattr((PyObject *) type, "__module__", str("pybind11_builtins"));
+    PYBIND11_SET_OLDPY_QUALNAME(type, name_obj);
+
+    assert(!PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC));
+    return (PyObject *) heap_type;
+}
+
+/// dynamic_attr: Allow the garbage collector to traverse the internal instance `__dict__`.
+extern "C" inline int pybind11_traverse(PyObject *self, visitproc visit, void *arg) {
+    PyObject *&dict = *_PyObject_GetDictPtr(self);
+    Py_VISIT(dict);
+// https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_traverse
+#if PY_VERSION_HEX >= 0x03090000
+    Py_VISIT(Py_TYPE(self));
+#endif
+    return 0;
+}
+
+/// dynamic_attr: Allow the GC to clear the dictionary.
+extern "C" inline int pybind11_clear(PyObject *self) {
+    PyObject *&dict = *_PyObject_GetDictPtr(self);
+    Py_CLEAR(dict);
+    return 0;
+}
+
+/// Give instances of this type a `__dict__` and opt into garbage collection.
+inline void enable_dynamic_attributes(PyHeapTypeObject *heap_type) {
+    auto *type = &heap_type->ht_type;
+    type->tp_flags |= Py_TPFLAGS_HAVE_GC;
+#if PY_VERSION_HEX < 0x030B0000
+    type->tp_dictoffset = type->tp_basicsize;           // place dict at the end
+    type->tp_basicsize += (ssize_t) sizeof(PyObject *); // and allocate enough space for it
+#else
+    type->tp_flags |= Py_TPFLAGS_MANAGED_DICT;
+#endif
+    type->tp_traverse = pybind11_traverse;
+    type->tp_clear = pybind11_clear;
+
+    static PyGetSetDef getset[] = {{
+#if PY_VERSION_HEX < 0x03070000
+                                       const_cast<char *>("__dict__"),
+#else
+                                       "__dict__",
+#endif
+                                       PyObject_GenericGetDict,
+                                       PyObject_GenericSetDict,
+                                       nullptr,
+                                       nullptr},
+                                   {nullptr, nullptr, nullptr, nullptr, nullptr}};
+    type->tp_getset = getset;
+}
+
+/// buffer_protocol: Fill in the view as specified by flags.
+extern "C" inline int pybind11_getbuffer(PyObject *obj, Py_buffer *view, int flags) {
+    // Look for a `get_buffer` implementation in this type's info or any bases (following MRO).
+    type_info *tinfo = nullptr;
+    for (auto type : reinterpret_borrow<tuple>(Py_TYPE(obj)->tp_mro)) {
+        tinfo = get_type_info((PyTypeObject *) type.ptr());
+        if (tinfo && tinfo->get_buffer) {
+            break;
+        }
+    }
+    if (view == nullptr || !tinfo || !tinfo->get_buffer) {
+        if (view) {
+            view->obj = nullptr;
+        }
+        PyErr_SetString(PyExc_BufferError, "pybind11_getbuffer(): Internal error");
+        return -1;
+    }
+    std::memset(view, 0, sizeof(Py_buffer));
+    buffer_info *info = tinfo->get_buffer(obj, tinfo->get_buffer_data);
+    if ((flags & PyBUF_WRITABLE) == PyBUF_WRITABLE && info->readonly) {
+        delete info;
+        // view->obj = nullptr;  // Was just memset to 0, so not necessary
+        PyErr_SetString(PyExc_BufferError, "Writable buffer requested for readonly storage");
+        return -1;
+    }
+    view->obj = obj;
+    view->ndim = 1;
+    view->internal = info;
+    view->buf = info->ptr;
+    view->itemsize = info->itemsize;
+    view->len = view->itemsize;
+    for (auto s : info->shape) {
+        view->len *= s;
+    }
+    view->readonly = static_cast<int>(info->readonly);
+    if ((flags & PyBUF_FORMAT) == PyBUF_FORMAT) {
+        view->format = const_cast<char *>(info->format.c_str());
+    }
+    if ((flags & PyBUF_STRIDES) == PyBUF_STRIDES) {
+        view->ndim = (int) info->ndim;
+        view->strides = info->strides.data();
+        view->shape = info->shape.data();
+    }
+    Py_INCREF(view->obj);
+    return 0;
+}
+
+/// buffer_protocol: Release the resources of the buffer.
+extern "C" inline void pybind11_releasebuffer(PyObject *, Py_buffer *view) {
+    delete (buffer_info *) view->internal;
+}
+
+/// Give this type a buffer interface.
+inline void enable_buffer_protocol(PyHeapTypeObject *heap_type) {
+    heap_type->ht_type.tp_as_buffer = &heap_type->as_buffer;
+
+    heap_type->as_buffer.bf_getbuffer = pybind11_getbuffer;
+    heap_type->as_buffer.bf_releasebuffer = pybind11_releasebuffer;
+}
+
+/** Create a brand new Python type according to the `type_record` specification.
+    Return value: New reference. */
+inline PyObject *make_new_python_type(const type_record &rec) {
+    auto name = reinterpret_steal<object>(PYBIND11_FROM_STRING(rec.name));
+
+    auto qualname = name;
+    if (rec.scope && !PyModule_Check(rec.scope.ptr()) && hasattr(rec.scope, "__qualname__")) {
+        qualname = reinterpret_steal<object>(
+            PyUnicode_FromFormat("%U.%U", rec.scope.attr("__qualname__").ptr(), name.ptr()));
+    }
+
+    object module_;
+    if (rec.scope) {
+        if (hasattr(rec.scope, "__module__")) {
+            module_ = rec.scope.attr("__module__");
+        } else if (hasattr(rec.scope, "__name__")) {
+            module_ = rec.scope.attr("__name__");
+        }
+    }
+
+    const auto *full_name = c_str(
+#if !defined(PYPY_VERSION)
+        module_ ? str(module_).cast<std::string>() + "." + rec.name :
+#endif
+                rec.name);
+
+    char *tp_doc = nullptr;
+    if (rec.doc && options::show_user_defined_docstrings()) {
+        /* Allocate memory for docstring (using PyObject_MALLOC, since
+           Python will free this later on) */
+        size_t size = std::strlen(rec.doc) + 1;
+        tp_doc = (char *) PyObject_MALLOC(size);
+        std::memcpy((void *) tp_doc, rec.doc, size);
+    }
+
+    auto &internals = get_internals();
+    auto bases = tuple(rec.bases);
+    auto *base = (bases.empty()) ? internals.instance_base : bases[0].ptr();
+
+    /* Danger zone: from now (and until PyType_Ready), make sure to
+       issue no Python C API calls which could potentially invoke the
+       garbage collector (the GC will call type_traverse(), which will in
+       turn find the newly constructed type in an invalid state) */
+    auto *metaclass
+        = rec.metaclass.ptr() ? (PyTypeObject *) rec.metaclass.ptr() : internals.default_metaclass;
+
+    auto *heap_type = (PyHeapTypeObject *) metaclass->tp_alloc(metaclass, 0);
+    if (!heap_type) {
+        pybind11_fail(std::string(rec.name) + ": Unable to create type object!");
+    }
+
+    heap_type->ht_name = name.release().ptr();
+#ifdef PYBIND11_BUILTIN_QUALNAME
+    heap_type->ht_qualname = qualname.inc_ref().ptr();
+#endif
+
+    auto *type = &heap_type->ht_type;
+    type->tp_name = full_name;
+    type->tp_doc = tp_doc;
+    type->tp_base = type_incref((PyTypeObject *) base);
+    type->tp_basicsize = static_cast<ssize_t>(sizeof(instance));
+    if (!bases.empty()) {
+        type->tp_bases = bases.release().ptr();
+    }
+
+    /* Don't inherit base __init__ */
+    type->tp_init = pybind11_object_init;
+
+    /* Supported protocols */
+    type->tp_as_number = &heap_type->as_number;
+    type->tp_as_sequence = &heap_type->as_sequence;
+    type->tp_as_mapping = &heap_type->as_mapping;
+    type->tp_as_async = &heap_type->as_async;
+
+    /* Flags */
+    type->tp_flags |= Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HEAPTYPE;
+    if (!rec.is_final) {
+        type->tp_flags |= Py_TPFLAGS_BASETYPE;
+    }
+
+    if (rec.dynamic_attr) {
+        enable_dynamic_attributes(heap_type);
+    }
+
+    if (rec.buffer_protocol) {
+        enable_buffer_protocol(heap_type);
+    }
+
+    if (rec.custom_type_setup_callback) {
+        rec.custom_type_setup_callback(heap_type);
+    }
+
+    if (PyType_Ready(type) < 0) {
+        pybind11_fail(std::string(rec.name) + ": PyType_Ready failed: " + error_string());
+    }
+
+    assert(!rec.dynamic_attr || PyType_HasFeature(type, Py_TPFLAGS_HAVE_GC));
+
+    /* Register type with the parent scope */
+    if (rec.scope) {
+        setattr(rec.scope, rec.name, (PyObject *) type);
+    } else {
+        Py_INCREF(type); // Keep it alive forever (reference leak)
+    }
+
+    if (module_) { // Needed by pydoc
+        setattr((PyObject *) type, "__module__", module_);
+    }
+
+    PYBIND11_SET_OLDPY_QUALNAME(type, qualname);
+
+    return (PyObject *) type;
+}
+
+PYBIND11_NAMESPACE_END(detail)
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/Patches/pybind11/detail/common.h b/Patches/pybind11/detail/common.h
new file mode 100644
index 00000000..db8c70b0
--- /dev/null
+++ b/Patches/pybind11/detail/common.h
@@ -0,0 +1,1240 @@
+/*
+    pybind11/detail/common.h -- Basic macros
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#pragma once
+
+#define PYBIND11_VERSION_MAJOR 2
+#define PYBIND11_VERSION_MINOR 10
+#define PYBIND11_VERSION_PATCH 3
+
+// Similar to Python's convention: https://docs.python.org/3/c-api/apiabiversion.html
+// Additional convention: 0xD = dev
+#define PYBIND11_VERSION_HEX 0x020A0300
+
+// Define some generic pybind11 helper macros for warning management.
+//
+// Note that compiler-specific push/pop pairs are baked into the
+// PYBIND11_NAMESPACE_BEGIN/PYBIND11_NAMESPACE_END pair of macros. Therefore manual
+// PYBIND11_WARNING_PUSH/PYBIND11_WARNING_POP are usually only needed in `#include` sections.
+//
+// If you find you need to suppress a warning, please try to make the suppression as local as
+// possible using these macros. Please also be sure to push/pop with the pybind11 macros. Please
+// only use compiler specifics if you need to check specific versions, e.g. Apple Clang vs. vanilla
+// Clang.
+#if defined(_MSC_VER)
+#    define PYBIND11_COMPILER_MSVC
+#    define PYBIND11_PRAGMA(...) __pragma(__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(warning(push))
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(warning(pop))
+#elif defined(__INTEL_COMPILER)
+#    define PYBIND11_COMPILER_INTEL
+#    define PYBIND11_PRAGMA(...) _Pragma(#__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(warning push)
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(warning pop)
+#elif defined(__clang__)
+#    define PYBIND11_COMPILER_CLANG
+#    define PYBIND11_PRAGMA(...) _Pragma(#__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(clang diagnostic push)
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(clang diagnostic push)
+#elif defined(__GNUC__)
+#    define PYBIND11_COMPILER_GCC
+#    define PYBIND11_PRAGMA(...) _Pragma(#__VA_ARGS__)
+#    define PYBIND11_WARNING_PUSH PYBIND11_PRAGMA(GCC diagnostic push)
+#    define PYBIND11_WARNING_POP PYBIND11_PRAGMA(GCC diagnostic pop)
+#endif
+
+#ifdef PYBIND11_COMPILER_MSVC
+#    define PYBIND11_WARNING_DISABLE_MSVC(name) PYBIND11_PRAGMA(warning(disable : name))
+#else
+#    define PYBIND11_WARNING_DISABLE_MSVC(name)
+#endif
+
+#ifdef PYBIND11_COMPILER_CLANG
+#    define PYBIND11_WARNING_DISABLE_CLANG(name) PYBIND11_PRAGMA(clang diagnostic ignored name)
+#else
+#    define PYBIND11_WARNING_DISABLE_CLANG(name)
+#endif
+
+#ifdef PYBIND11_COMPILER_GCC
+#    define PYBIND11_WARNING_DISABLE_GCC(name) PYBIND11_PRAGMA(GCC diagnostic ignored name)
+#else
+#    define PYBIND11_WARNING_DISABLE_GCC(name)
+#endif
+
+#ifdef PYBIND11_COMPILER_INTEL
+#    define PYBIND11_WARNING_DISABLE_INTEL(name) PYBIND11_PRAGMA(warning disable name)
+#else
+#    define PYBIND11_WARNING_DISABLE_INTEL(name)
+#endif
+
+#define PYBIND11_NAMESPACE_BEGIN(name)                                                            \
+    namespace name {                                                                              \
+    PYBIND11_WARNING_PUSH
+
+#define PYBIND11_NAMESPACE_END(name)                                                              \
+    PYBIND11_WARNING_POP                                                                          \
+    }
+
+// Robust support for some features and loading modules compiled against different pybind versions
+// requires forcing hidden visibility on pybind code, so we enforce this by setting the attribute
+// on the main `pybind11` namespace.
+#if !defined(PYBIND11_NAMESPACE)
+#    ifdef __GNUG__
+#        define PYBIND11_NAMESPACE pybind11 __attribute__((visibility("hidden")))
+#    else
+#        define PYBIND11_NAMESPACE pybind11
+#    endif
+#endif
+
+#if !(defined(_MSC_VER) && __cplusplus == 199711L)
+#    if __cplusplus >= 201402L
+#        define PYBIND11_CPP14
+#        if __cplusplus >= 201703L
+#            define PYBIND11_CPP17
+#            if __cplusplus >= 202002L
+#                define PYBIND11_CPP20
+// Please update tests/pybind11_tests.cpp `cpp_std()` when adding a macro here.
+#            endif
+#        endif
+#    endif
+#elif defined(_MSC_VER) && __cplusplus == 199711L
+// MSVC sets _MSVC_LANG rather than __cplusplus (supposedly until the standard is fully
+// implemented). Unless you use the /Zc:__cplusplus flag on Visual Studio 2017 15.7 Preview 3
+// or newer.
+#    if _MSVC_LANG >= 201402L
+#        define PYBIND11_CPP14
+#        if _MSVC_LANG > 201402L
+#            define PYBIND11_CPP17
+#            if _MSVC_LANG >= 202002L
+#                define PYBIND11_CPP20
+#            endif
+#        endif
+#    endif
+#endif
+
+// Compiler version assertions
+#if defined(__INTEL_COMPILER)
+#    if __INTEL_COMPILER < 1800
+#        error pybind11 requires Intel C++ compiler v18 or newer
+#    elif __INTEL_COMPILER < 1900 && defined(PYBIND11_CPP14)
+#        error pybind11 supports only C++11 with Intel C++ compiler v18. Use v19 or newer for C++14.
+#    endif
+/* The following pragma cannot be pop'ed:
+   https://community.intel.com/t5/Intel-C-Compiler/Inline-and-no-inline-warning/td-p/1216764 */
+#    pragma warning disable 2196 // warning #2196: routine is both "inline" and "noinline"
+#elif defined(__clang__) && !defined(__apple_build_version__)
+#    if __clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ < 3)
+#        error pybind11 requires clang 3.3 or newer
+#    endif
+#elif defined(__clang__)
+// Apple changes clang version macros to its Xcode version; the first Xcode release based on
+// (upstream) clang 3.3 was Xcode 5:
+#    if __clang_major__ < 5
+#        error pybind11 requires Xcode/clang 5.0 or newer
+#    endif
+#elif defined(__GNUG__)
+#    if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 8)
+#        error pybind11 requires gcc 4.8 or newer
+#    endif
+#elif defined(_MSC_VER)
+#    if _MSC_VER < 1910
+#        error pybind11 2.10+ requires MSVC 2017 or newer
+#    endif
+#endif
+
+#if !defined(PYBIND11_EXPORT)
+#    if defined(WIN32) || defined(_WIN32)
+#        define PYBIND11_EXPORT __declspec(dllexport)
+#    else
+#        define PYBIND11_EXPORT __attribute__((visibility("default")))
+#    endif
+#endif
+
+#if !defined(PYBIND11_EXPORT_EXCEPTION)
+#    if defined(__apple_build_version__)
+#        define PYBIND11_EXPORT_EXCEPTION PYBIND11_EXPORT
+#    else
+#        define PYBIND11_EXPORT_EXCEPTION
+#    endif
+#endif
+
+// For CUDA, GCC7, GCC8:
+// PYBIND11_NOINLINE_FORCED is incompatible with `-Wattributes -Werror`.
+// When defining PYBIND11_NOINLINE_FORCED, it is best to also use `-Wno-attributes`.
+// However, the measured shared-library size saving when using noinline are only
+// 1.7% for CUDA, -0.2% for GCC7, and 0.0% for GCC8 (using -DCMAKE_BUILD_TYPE=MinSizeRel,
+// the default under pybind11/tests).
+#if !defined(PYBIND11_NOINLINE_FORCED)                                                            \
+    && (defined(__CUDACC__) || (defined(__GNUC__) && (__GNUC__ == 7 || __GNUC__ == 8)))
+#    define PYBIND11_NOINLINE_DISABLED
+#endif
+
+// The PYBIND11_NOINLINE macro is for function DEFINITIONS.
+// In contrast, FORWARD DECLARATIONS should never use this macro:
+// https://stackoverflow.com/questions/9317473/forward-declaration-of-inline-functions
+#if defined(PYBIND11_NOINLINE_DISABLED) // Option for maximum portability and experimentation.
+#    define PYBIND11_NOINLINE inline
+#elif defined(_MSC_VER)
+#    define PYBIND11_NOINLINE __declspec(noinline) inline
+#else
+#    define PYBIND11_NOINLINE __attribute__((noinline)) inline
+#endif
+
+#if defined(__MINGW32__)
+// For unknown reasons all PYBIND11_DEPRECATED member trigger a warning when declared
+// whether it is used or not
+#    define PYBIND11_DEPRECATED(reason)
+#elif defined(PYBIND11_CPP14)
+#    define PYBIND11_DEPRECATED(reason) [[deprecated(reason)]]
+#else
+#    define PYBIND11_DEPRECATED(reason) __attribute__((deprecated(reason)))
+#endif
+
+#if defined(PYBIND11_CPP17)
+#    define PYBIND11_MAYBE_UNUSED [[maybe_unused]]
+#elif defined(_MSC_VER) && !defined(__clang__)
+#    define PYBIND11_MAYBE_UNUSED
+#else
+#    define PYBIND11_MAYBE_UNUSED __attribute__((__unused__))
+#endif
+
+/* Don't let Python.h #define (v)snprintf as macro because they are implemented
+   properly in Visual Studio since 2015. */
+#if defined(_MSC_VER)
+#    define HAVE_SNPRINTF 1
+#endif
+
+/// Include Python header, disable linking to pythonX_d.lib on Windows in debug mode
+#if defined(_MSC_VER)
+PYBIND11_WARNING_PUSH
+PYBIND11_WARNING_DISABLE_MSVC(4505)
+// C4505: 'PySlice_GetIndicesEx': unreferenced local function has been removed (PyPy only)
+#    if defined(_DEBUG) && !defined(Py_DEBUG)
+// Workaround for a VS 2022 issue.
+// NOTE: This workaround knowingly violates the Python.h include order requirement:
+// https://docs.python.org/3/c-api/intro.html#include-files
+// See https://github.com/pybind/pybind11/pull/3497 for full context.
+#        include <yvals.h>
+#        if _MSVC_STL_VERSION >= 143
+#            include <crtdefs.h>
+#        endif
+#        define PYBIND11_DEBUG_MARKER
+#        undef _DEBUG
+#    endif
+#endif
+
+// https://en.cppreference.com/w/c/chrono/localtime
+#if defined(__STDC_LIB_EXT1__) && !defined(__STDC_WANT_LIB_EXT1__)
+#    define __STDC_WANT_LIB_EXT1__
+#endif
+
+#ifdef __has_include
+// std::optional (but including it in c++14 mode isn't allowed)
+#    if defined(PYBIND11_CPP17) && __has_include(<optional>)
+#        define PYBIND11_HAS_OPTIONAL 1
+#    endif
+// std::experimental::optional (but not allowed in c++11 mode)
+#    if defined(PYBIND11_CPP14) && (__has_include(<experimental/optional>) && \
+                                 !__has_include(<optional>))
+#        define PYBIND11_HAS_EXP_OPTIONAL 1
+#    endif
+// std::variant
+#    if defined(PYBIND11_CPP17) && __has_include(<variant>)
+#        define PYBIND11_HAS_VARIANT 1
+#    endif
+#elif defined(_MSC_VER) && defined(PYBIND11_CPP17)
+#    define PYBIND11_HAS_OPTIONAL 1
+#    define PYBIND11_HAS_VARIANT 1
+#endif
+
+#if defined(PYBIND11_CPP17)
+#    if defined(__has_include)
+#        if __has_include(<string_view>)
+#            define PYBIND11_HAS_STRING_VIEW
+#        endif
+#    elif defined(_MSC_VER)
+#        define PYBIND11_HAS_STRING_VIEW
+#    endif
+#endif
+
+#include <Python.h>
+// Reminder: WITH_THREAD is always defined if PY_VERSION_HEX >= 0x03070000
+#if PY_VERSION_HEX < 0x03060000
+#    error "PYTHON < 3.6 IS UNSUPPORTED. pybind11 v2.9 was the last to support Python 2 and 3.5."
+#endif
+#include <frameobject.h>
+#include <pythread.h>
+
+/* Python #defines overrides on all sorts of core functions, which
+   tends to weak havok in C++ codebases that expect these to work
+   like regular functions (potentially with several overloads) */
+#if defined(isalnum)
+#    undef isalnum
+#    undef isalpha
+#    undef islower
+#    undef isspace
+#    undef isupper
+#    undef tolower
+#    undef toupper
+#endif
+
+#if defined(copysign)
+#    undef copysign
+#endif
+
+#if defined(PYPY_VERSION) && !defined(PYBIND11_SIMPLE_GIL_MANAGEMENT)
+#    define PYBIND11_SIMPLE_GIL_MANAGEMENT
+#endif
+
+#if defined(_MSC_VER)
+#    if defined(PYBIND11_DEBUG_MARKER)
+#        define _DEBUG
+#        undef PYBIND11_DEBUG_MARKER
+#    endif
+PYBIND11_WARNING_POP
+#endif
+
+#include <cstddef>
+#include <cstring>
+#include <exception>
+#include <forward_list>
+#include <memory>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+#include <typeindex>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+#if defined(__has_include)
+#    if __has_include(<version>)
+#        include <version>
+#    endif
+#endif
+
+// Must be after including <version> or one of the other headers specified by the standard
+#if defined(__cpp_lib_char8_t) && __cpp_lib_char8_t >= 201811L
+#    define PYBIND11_HAS_U8STRING
+#endif
+
+// See description of PR #4246:
+#if !defined(NDEBUG) && !defined(PY_ASSERT_GIL_HELD_INCREF_DECREF)                                \
+    && !(defined(PYPY_VERSION)                                                                    \
+         && defined(_MSC_VER)) /* PyPy Windows: pytest hangs indefinitely at the end of the       \
+                                  process (see PR #4268) */                                       \
+    && !defined(PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF)
+// The following define will be enabled by default in the 2.11 release
+// define PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF
+#endif
+
+// #define PYBIND11_STR_LEGACY_PERMISSIVE
+// If DEFINED, pybind11::str can hold PyUnicodeObject or PyBytesObject
+//             (probably surprising and never documented, but this was the
+//             legacy behavior until and including v2.6.x). As a side-effect,
+//             pybind11::isinstance<str>() is true for both pybind11::str and
+//             pybind11::bytes.
+// If UNDEFINED, pybind11::str can only hold PyUnicodeObject, and
+//               pybind11::isinstance<str>() is true only for pybind11::str.
+//               However, for Python 2 only (!), the pybind11::str caster
+//               implicitly decoded bytes to PyUnicodeObject. This was to ease
+//               the transition from the legacy behavior to the non-permissive
+//               behavior.
+
+/// Compatibility macros for Python 2 / Python 3 versions TODO: remove
+#define PYBIND11_INSTANCE_METHOD_NEW(ptr, class_) PyInstanceMethod_New(ptr)
+#define PYBIND11_INSTANCE_METHOD_CHECK PyInstanceMethod_Check
+#define PYBIND11_INSTANCE_METHOD_GET_FUNCTION PyInstanceMethod_GET_FUNCTION
+#define PYBIND11_BYTES_CHECK PyBytes_Check
+#define PYBIND11_BYTES_FROM_STRING PyBytes_FromString
+#define PYBIND11_BYTES_FROM_STRING_AND_SIZE PyBytes_FromStringAndSize
+#define PYBIND11_BYTES_AS_STRING_AND_SIZE PyBytes_AsStringAndSize
+#define PYBIND11_BYTES_AS_STRING PyBytes_AsString
+#define PYBIND11_BYTES_SIZE PyBytes_Size
+#define PYBIND11_LONG_CHECK(o) PyLong_Check(o)
+#define PYBIND11_LONG_AS_LONGLONG(o) PyLong_AsLongLong(o)
+#define PYBIND11_LONG_FROM_SIGNED(o) PyLong_FromSsize_t((ssize_t) (o))
+#define PYBIND11_LONG_FROM_UNSIGNED(o) PyLong_FromSize_t((size_t) (o))
+#define PYBIND11_BYTES_NAME "bytes"
+#define PYBIND11_STRING_NAME "str"
+#define PYBIND11_SLICE_OBJECT PyObject
+#define PYBIND11_FROM_STRING PyUnicode_FromString
+#define PYBIND11_STR_TYPE ::pybind11::str
+#define PYBIND11_BOOL_ATTR "__bool__"
+#define PYBIND11_NB_BOOL(ptr) ((ptr)->nb_bool)
+#define PYBIND11_BUILTINS_MODULE "builtins"
+// Providing a separate declaration to make Clang's -Wmissing-prototypes happy.
+// See comment for PYBIND11_MODULE below for why this is marked "maybe unused".
+#define PYBIND11_PLUGIN_IMPL(name)                                                                \
+    extern "C" PYBIND11_MAYBE_UNUSED PYBIND11_EXPORT PyObject *PyInit_##name();                   \
+    extern "C" PYBIND11_EXPORT PyObject *PyInit_##name()
+
+#define PYBIND11_TRY_NEXT_OVERLOAD ((PyObject *) 1) // special failure return code
+#define PYBIND11_STRINGIFY(x) #x
+#define PYBIND11_TOSTRING(x) PYBIND11_STRINGIFY(x)
+#define PYBIND11_CONCAT(first, second) first##second
+#define PYBIND11_ENSURE_INTERNALS_READY pybind11::detail::get_internals();
+
+#define PYBIND11_CHECK_PYTHON_VERSION                                                             \
+    {                                                                                             \
+        const char *compiled_ver                                                                  \
+            = PYBIND11_TOSTRING(PY_MAJOR_VERSION) "." PYBIND11_TOSTRING(PY_MINOR_VERSION);        \
+        const char *runtime_ver = Py_GetVersion();                                                \
+        size_t len = std::strlen(compiled_ver);                                                   \
+        if (std::strncmp(runtime_ver, compiled_ver, len) != 0                                     \
+            || (runtime_ver[len] >= '0' && runtime_ver[len] <= '9')) {                            \
+            PyErr_Format(PyExc_ImportError,                                                       \
+                         "Python version mismatch: module was compiled for Python %s, "           \
+                         "but the interpreter version is incompatible: %s.",                      \
+                         compiled_ver,                                                            \
+                         runtime_ver);                                                            \
+            return nullptr;                                                                       \
+        }                                                                                         \
+    }
+
+#define PYBIND11_CATCH_INIT_EXCEPTIONS                                                            \
+    catch (pybind11::error_already_set & e) {                                                     \
+        pybind11::raise_from(e, PyExc_ImportError, "initialization failed");                      \
+        return nullptr;                                                                           \
+    }                                                                                             \
+    catch (const std::exception &e) {                                                             \
+        PyErr_SetString(PyExc_ImportError, e.what());                                             \
+        return nullptr;                                                                           \
+    }
+
+/** \rst
+    ***Deprecated in favor of PYBIND11_MODULE***
+
+    This macro creates the entry point that will be invoked when the Python interpreter
+    imports a plugin library. Please create a `module_` in the function body and return
+    the pointer to its underlying Python object at the end.
+
+    .. code-block:: cpp
+
+        PYBIND11_PLUGIN(example) {
+            pybind11::module_ m("example", "pybind11 example plugin");
+            /// Set up bindings here
+            return m.ptr();
+        }
+\endrst */
+#define PYBIND11_PLUGIN(name)                                                                     \
+    PYBIND11_DEPRECATED("PYBIND11_PLUGIN is deprecated, use PYBIND11_MODULE")                     \
+    static PyObject *pybind11_init();                                                             \
+    PYBIND11_PLUGIN_IMPL(name) {                                                                  \
+        PYBIND11_CHECK_PYTHON_VERSION                                                             \
+        PYBIND11_ENSURE_INTERNALS_READY                                                           \
+        try {                                                                                     \
+            return pybind11_init();                                                               \
+        }                                                                                         \
+        PYBIND11_CATCH_INIT_EXCEPTIONS                                                            \
+    }                                                                                             \
+    PyObject *pybind11_init()
+
+/** \rst
+    This macro creates the entry point that will be invoked when the Python interpreter
+    imports an extension module. The module name is given as the fist argument and it
+    should not be in quotes. The second macro argument defines a variable of type
+    `py::module_` which can be used to initialize the module.
+
+    The entry point is marked as "maybe unused" to aid dead-code detection analysis:
+    since the entry point is typically only looked up at runtime and not referenced
+    during translation, it would otherwise appear as unused ("dead") code.
+
+    .. code-block:: cpp
+
+        PYBIND11_MODULE(example, m) {
+            m.doc() = "pybind11 example module";
+
+            // Add bindings here
+            m.def("foo", []() {
+                return "Hello, World!";
+            });
+        }
+\endrst */
+#define PYBIND11_MODULE(name, variable)                                                           \
+    static ::pybind11::module_::module_def PYBIND11_CONCAT(pybind11_module_def_, name)            \
+        PYBIND11_MAYBE_UNUSED;                                                                    \
+    PYBIND11_MAYBE_UNUSED                                                                         \
+    static void PYBIND11_CONCAT(pybind11_init_, name)(::pybind11::module_ &);                     \
+    PYBIND11_PLUGIN_IMPL(name) {                                                                  \
+        PYBIND11_CHECK_PYTHON_VERSION                                                             \
+        PYBIND11_ENSURE_INTERNALS_READY                                                           \
+        auto m = ::pybind11::module_::create_extension_module(                                    \
+            PYBIND11_TOSTRING(name), nullptr, &PYBIND11_CONCAT(pybind11_module_def_, name));      \
+        try {                                                                                     \
+            PYBIND11_CONCAT(pybind11_init_, name)(m);                                             \
+            return m.ptr();                                                                       \
+        }                                                                                         \
+        PYBIND11_CATCH_INIT_EXCEPTIONS                                                            \
+    }                                                                                             \
+    void PYBIND11_CONCAT(pybind11_init_, name)(::pybind11::module_ & (variable))
+
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+using ssize_t = Py_ssize_t;
+using size_t = std::size_t;
+
+template <typename IntType>
+inline ssize_t ssize_t_cast(const IntType &val) {
+    static_assert(sizeof(IntType) <= sizeof(ssize_t), "Implicit narrowing is not permitted.");
+    return static_cast<ssize_t>(val);
+}
+
+/// Approach used to cast a previously unknown C++ instance into a Python object
+enum class return_value_policy : uint8_t {
+    /** This is the default return value policy, which falls back to the policy
+        return_value_policy::take_ownership when the return value is a pointer.
+        Otherwise, it uses return_value::move or return_value::copy for rvalue
+        and lvalue references, respectively. See below for a description of what
+        all of these different policies do. */
+    automatic = 0,
+
+    /** As above, but use policy return_value_policy::reference when the return
+        value is a pointer. This is the default conversion policy for function
+        arguments when calling Python functions manually from C++ code (i.e. via
+        handle::operator()). You probably won't need to use this. */
+    automatic_reference,
+
+    /** Reference an existing object (i.e. do not create a new copy) and take
+        ownership. Python will call the destructor and delete operator when the
+        object's reference count reaches zero. Undefined behavior ensues when
+        the C++ side does the same.. */
+    take_ownership,
+
+    /** Create a new copy of the returned object, which will be owned by
+        Python. This policy is comparably safe because the lifetimes of the two
+        instances are decoupled. */
+    copy,
+
+    /** Use std::move to move the return value contents into a new instance
+        that will be owned by Python. This policy is comparably safe because the
+        lifetimes of the two instances (move source and destination) are
+        decoupled. */
+    move,
+
+    /** Reference an existing object, but do not take ownership. The C++ side
+        is responsible for managing the object's lifetime and deallocating it
+        when it is no longer used. Warning: undefined behavior will ensue when
+        the C++ side deletes an object that is still referenced and used by
+        Python. */
+    reference,
+
+    /** This policy only applies to methods and properties. It references the
+        object without taking ownership similar to the above
+        return_value_policy::reference policy. In contrast to that policy, the
+        function or property's implicit this argument (called the parent) is
+        considered to be the the owner of the return value (the child).
+        pybind11 then couples the lifetime of the parent to the child via a
+        reference relationship that ensures that the parent cannot be garbage
+        collected while Python is still using the child. More advanced
+        variations of this scheme are also possible using combinations of
+        return_value_policy::reference and the keep_alive call policy */
+    reference_internal
+};
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+inline static constexpr int log2(size_t n, int k = 0) {
+    return (n <= 1) ? k : log2(n >> 1, k + 1);
+}
+
+// Returns the size as a multiple of sizeof(void *), rounded up.
+inline static constexpr size_t size_in_ptrs(size_t s) {
+    return 1 + ((s - 1) >> log2(sizeof(void *)));
+}
+
+/**
+ * The space to allocate for simple layout instance holders (see below) in multiple of the size of
+ * a pointer (e.g.  2 means 16 bytes on 64-bit architectures).  The default is the minimum required
+ * to holder either a std::unique_ptr or std::shared_ptr (which is almost always
+ * sizeof(std::shared_ptr<T>)).
+ */
+constexpr size_t instance_simple_holder_in_ptrs() {
+    static_assert(sizeof(std::shared_ptr<int>) >= sizeof(std::unique_ptr<int>),
+                  "pybind assumes std::shared_ptrs are at least as big as std::unique_ptrs");
+    return size_in_ptrs(sizeof(std::shared_ptr<int>));
+}
+
+// Forward declarations
+struct type_info;
+struct value_and_holder;
+
+struct nonsimple_values_and_holders {
+    void **values_and_holders;
+    uint8_t *status;
+};
+
+/// The 'instance' type which needs to be standard layout (need to be able to use 'offsetof')
+struct instance {
+    PyObject_HEAD
+    /// Storage for pointers and holder; see simple_layout, below, for a description
+    union {
+        void *simple_value_holder[1 + instance_simple_holder_in_ptrs()];
+        nonsimple_values_and_holders nonsimple;
+    };
+    /// Weak references
+    PyObject *weakrefs;
+    /// If true, the pointer is owned which means we're free to manage it with a holder.
+    bool owned : 1;
+    /**
+     * An instance has two possible value/holder layouts.
+     *
+     * Simple layout (when this flag is true), means the `simple_value_holder` is set with a
+     * pointer and the holder object governing that pointer, i.e. [val1*][holder].  This layout is
+     * applied whenever there is no python-side multiple inheritance of bound C++ types *and* the
+     * type's holder will fit in the default space (which is large enough to hold either a
+     * std::unique_ptr or std::shared_ptr).
+     *
+     * Non-simple layout applies when using custom holders that require more space than
+     * `shared_ptr` (which is typically the size of two pointers), or when multiple inheritance is
+     * used on the python side.  Non-simple layout allocates the required amount of memory to have
+     * multiple bound C++ classes as parents.  Under this layout, `nonsimple.values_and_holders` is
+     * set to a pointer to allocated space of the required space to hold a sequence of value
+     * pointers and holders followed `status`, a set of bit flags (1 byte each), i.e.
+     * [val1*][holder1][val2*][holder2]...[bb...]  where each [block] is rounded up to a multiple
+     * of `sizeof(void *)`.  `nonsimple.status` is, for convenience, a pointer to the beginning of
+     * the [bb...] block (but not independently allocated).
+     *
+     * Status bits indicate whether the associated holder is constructed (&
+     * status_holder_constructed) and whether the value pointer is registered (&
+     * status_instance_registered) in `registered_instances`.
+     */
+    bool simple_layout : 1;
+    /// For simple layout, tracks whether the holder has been constructed
+    bool simple_holder_constructed : 1;
+    /// For simple layout, tracks whether the instance is registered in `registered_instances`
+    bool simple_instance_registered : 1;
+    /// If true, get_internals().patients has an entry for this object
+    bool has_patients : 1;
+    /// If true, the type of this instance has an associated alias class (set via `init_instance`)
+    bool has_alias : 1;
+    /// If true, this instance has an associated alias class and was constructed by Python
+    bool is_alias : 1;
+
+    /// Initializes all of the above type/values/holders data (but not the instance values
+    /// themselves)
+    void allocate_layout();
+
+    /// Destroys/deallocates all of the above
+    void deallocate_layout();
+
+    /// Returns the value_and_holder wrapper for the given type (or the first, if `find_type`
+    /// omitted).  Returns a default-constructed (with `.inst = nullptr`) object on failure if
+    /// `throw_if_missing` is false.
+    value_and_holder get_value_and_holder(const type_info *find_type = nullptr,
+                                          bool throw_if_missing = true);
+
+    /// Bit values for the non-simple status flags
+    static constexpr uint8_t status_holder_constructed = 1;
+    static constexpr uint8_t status_instance_registered = 2;
+};
+
+static_assert(std::is_standard_layout<instance>::value,
+              "Internal error: `pybind11::detail::instance` is not standard layout!");
+
+/// from __cpp_future__ import (convenient aliases from C++14/17)
+#if defined(PYBIND11_CPP14)
+using std::conditional_t;
+using std::enable_if_t;
+using std::remove_cv_t;
+using std::remove_reference_t;
+#else
+template <bool B, typename T = void>
+using enable_if_t = typename std::enable_if<B, T>::type;
+template <bool B, typename T, typename F>
+using conditional_t = typename std::conditional<B, T, F>::type;
+template <typename T>
+using remove_cv_t = typename std::remove_cv<T>::type;
+template <typename T>
+using remove_reference_t = typename std::remove_reference<T>::type;
+#endif
+
+#if defined(PYBIND11_CPP20)
+using std::remove_cvref;
+using std::remove_cvref_t;
+#else
+template <class T>
+struct remove_cvref {
+    using type = remove_cv_t<remove_reference_t<T>>;
+};
+template <class T>
+using remove_cvref_t = typename remove_cvref<T>::type;
+#endif
+
+/// Index sequences
+#if defined(PYBIND11_CPP14)
+using std::index_sequence;
+using std::make_index_sequence;
+#else
+template <size_t...>
+struct index_sequence {};
+template <size_t N, size_t... S>
+struct make_index_sequence_impl : make_index_sequence_impl<N - 1, N - 1, S...> {};
+template <size_t... S>
+struct make_index_sequence_impl<0, S...> {
+    using type = index_sequence<S...>;
+};
+template <size_t N>
+using make_index_sequence = typename make_index_sequence_impl<N>::type;
+#endif
+
+/// Make an index sequence of the indices of true arguments
+template <typename ISeq, size_t, bool...>
+struct select_indices_impl {
+    using type = ISeq;
+};
+template <size_t... IPrev, size_t I, bool B, bool... Bs>
+struct select_indices_impl<index_sequence<IPrev...>, I, B, Bs...>
+    : select_indices_impl<conditional_t<B, index_sequence<IPrev..., I>, index_sequence<IPrev...>>,
+                          I + 1,
+                          Bs...> {};
+template <bool... Bs>
+using select_indices = typename select_indices_impl<index_sequence<>, 0, Bs...>::type;
+
+/// Backports of std::bool_constant and std::negation to accommodate older compilers
+template <bool B>
+using bool_constant = std::integral_constant<bool, B>;
+template <typename T>
+struct negation : bool_constant<!T::value> {};
+
+// PGI/Intel cannot detect operator delete with the "compatible" void_t impl, so
+// using the new one (C++14 defect, so generally works on newer compilers, even
+// if not in C++17 mode)
+#if defined(__PGIC__) || defined(__INTEL_COMPILER)
+template <typename...>
+using void_t = void;
+#else
+template <typename...>
+struct void_t_impl {
+    using type = void;
+};
+template <typename... Ts>
+using void_t = typename void_t_impl<Ts...>::type;
+#endif
+
+/// Compile-time all/any/none of that check the boolean value of all template types
+#if defined(__cpp_fold_expressions) && !(defined(_MSC_VER) && (_MSC_VER < 1916))
+template <class... Ts>
+using all_of = bool_constant<(Ts::value && ...)>;
+template <class... Ts>
+using any_of = bool_constant<(Ts::value || ...)>;
+#elif !defined(_MSC_VER)
+template <bool...>
+struct bools {};
+template <class... Ts>
+using all_of = std::is_same<bools<Ts::value..., true>, bools<true, Ts::value...>>;
+template <class... Ts>
+using any_of = negation<all_of<negation<Ts>...>>;
+#else
+// MSVC has trouble with the above, but supports std::conjunction, which we can use instead (albeit
+// at a slight loss of compilation efficiency).
+template <class... Ts>
+using all_of = std::conjunction<Ts...>;
+template <class... Ts>
+using any_of = std::disjunction<Ts...>;
+#endif
+template <class... Ts>
+using none_of = negation<any_of<Ts...>>;
+
+template <class T, template <class> class... Predicates>
+using satisfies_all_of = all_of<Predicates<T>...>;
+template <class T, template <class> class... Predicates>
+using satisfies_any_of = any_of<Predicates<T>...>;
+template <class T, template <class> class... Predicates>
+using satisfies_none_of = none_of<Predicates<T>...>;
+
+/// Strip the class from a method type
+template <typename T>
+struct remove_class {};
+template <typename C, typename R, typename... A>
+struct remove_class<R (C::*)(A...)> {
+    using type = R(A...);
+};
+template <typename C, typename R, typename... A>
+struct remove_class<R (C::*)(A...) const> {
+    using type = R(A...);
+};
+
+/// Helper template to strip away type modifiers
+template <typename T>
+struct intrinsic_type {
+    using type = T;
+};
+template <typename T>
+struct intrinsic_type<const T> {
+    using type = typename intrinsic_type<T>::type;
+};
+template <typename T>
+struct intrinsic_type<T *> {
+    using type = typename intrinsic_type<T>::type;
+};
+template <typename T>
+struct intrinsic_type<T &> {
+    using type = typename intrinsic_type<T>::type;
+};
+template <typename T>
+struct intrinsic_type<T &&> {
+    using type = typename intrinsic_type<T>::type;
+};
+template <typename T, size_t N>
+struct intrinsic_type<const T[N]> {
+    using type = typename intrinsic_type<T>::type;
+};
+template <typename T, size_t N>
+struct intrinsic_type<T[N]> {
+    using type = typename intrinsic_type<T>::type;
+};
+template <typename T>
+using intrinsic_t = typename intrinsic_type<T>::type;
+
+/// Helper type to replace 'void' in some expressions
+struct void_type {};
+
+/// Helper template which holds a list of types
+template <typename...>
+struct type_list {};
+
+/// Compile-time integer sum
+#ifdef __cpp_fold_expressions
+template <typename... Ts>
+constexpr size_t constexpr_sum(Ts... ns) {
+    return (0 + ... + size_t{ns});
+}
+#else
+constexpr size_t constexpr_sum() { return 0; }
+template <typename T, typename... Ts>
+constexpr size_t constexpr_sum(T n, Ts... ns) {
+    return size_t{n} + constexpr_sum(ns...);
+}
+#endif
+
+PYBIND11_NAMESPACE_BEGIN(constexpr_impl)
+/// Implementation details for constexpr functions
+constexpr int first(int i) { return i; }
+template <typename T, typename... Ts>
+constexpr int first(int i, T v, Ts... vs) {
+    return v ? i : first(i + 1, vs...);
+}
+
+constexpr int last(int /*i*/, int result) { return result; }
+template <typename T, typename... Ts>
+constexpr int last(int i, int result, T v, Ts... vs) {
+    return last(i + 1, v ? i : result, vs...);
+}
+PYBIND11_NAMESPACE_END(constexpr_impl)
+
+/// Return the index of the first type in Ts which satisfies Predicate<T>.
+/// Returns sizeof...(Ts) if none match.
+template <template <typename> class Predicate, typename... Ts>
+constexpr int constexpr_first() {
+    return constexpr_impl::first(0, Predicate<Ts>::value...);
+}
+
+/// Return the index of the last type in Ts which satisfies Predicate<T>, or -1 if none match.
+template <template <typename> class Predicate, typename... Ts>
+constexpr int constexpr_last() {
+    return constexpr_impl::last(0, -1, Predicate<Ts>::value...);
+}
+
+/// Return the Nth element from the parameter pack
+template <size_t N, typename T, typename... Ts>
+struct pack_element {
+    using type = typename pack_element<N - 1, Ts...>::type;
+};
+template <typename T, typename... Ts>
+struct pack_element<0, T, Ts...> {
+    using type = T;
+};
+
+/// Return the one and only type which matches the predicate, or Default if none match.
+/// If more than one type matches the predicate, fail at compile-time.
+template <template <typename> class Predicate, typename Default, typename... Ts>
+struct exactly_one {
+    static constexpr auto found = constexpr_sum(Predicate<Ts>::value...);
+    static_assert(found <= 1, "Found more than one type matching the predicate");
+
+    static constexpr auto index = found ? constexpr_first<Predicate, Ts...>() : 0;
+    using type = conditional_t<found, typename pack_element<index, Ts...>::type, Default>;
+};
+template <template <typename> class P, typename Default>
+struct exactly_one<P, Default> {
+    using type = Default;
+};
+
+template <template <typename> class Predicate, typename Default, typename... Ts>
+using exactly_one_t = typename exactly_one<Predicate, Default, Ts...>::type;
+
+/// Defer the evaluation of type T until types Us are instantiated
+template <typename T, typename... /*Us*/>
+struct deferred_type {
+    using type = T;
+};
+template <typename T, typename... Us>
+using deferred_t = typename deferred_type<T, Us...>::type;
+
+/// Like is_base_of, but requires a strict base (i.e. `is_strict_base_of<T, T>::value == false`,
+/// unlike `std::is_base_of`)
+template <typename Base, typename Derived>
+using is_strict_base_of
+    = bool_constant<std::is_base_of<Base, Derived>::value && !std::is_same<Base, Derived>::value>;
+
+/// Like is_base_of, but also requires that the base type is accessible (i.e. that a Derived
+/// pointer can be converted to a Base pointer) For unions, `is_base_of<T, T>::value` is False, so
+/// we need to check `is_same` as well.
+template <typename Base, typename Derived>
+using is_accessible_base_of
+    = bool_constant<(std::is_same<Base, Derived>::value || std::is_base_of<Base, Derived>::value)
+                    && std::is_convertible<Derived *, Base *>::value>;
+
+template <template <typename...> class Base>
+struct is_template_base_of_impl {
+    template <typename... Us>
+    static std::true_type check(Base<Us...> *);
+    static std::false_type check(...);
+};
+
+/// Check if a template is the base of a type. For example:
+/// `is_template_base_of<Base, T>` is true if `struct T : Base<U> {}` where U can be anything
+template <template <typename...> class Base, typename T>
+// Sadly, all MSVC versions incl. 2022 need the workaround, even in C++20 mode.
+// See also: https://github.com/pybind/pybind11/pull/3741
+#if !defined(_MSC_VER)
+using is_template_base_of
+    = decltype(is_template_base_of_impl<Base>::check((intrinsic_t<T> *) nullptr));
+#else
+struct is_template_base_of
+    : decltype(is_template_base_of_impl<Base>::check((intrinsic_t<T> *) nullptr)) {
+};
+#endif
+
+/// Check if T is an instantiation of the template `Class`. For example:
+/// `is_instantiation<shared_ptr, T>` is true if `T == shared_ptr<U>` where U can be anything.
+template <template <typename...> class Class, typename T>
+struct is_instantiation : std::false_type {};
+template <template <typename...> class Class, typename... Us>
+struct is_instantiation<Class, Class<Us...>> : std::true_type {};
+
+/// Check if T is std::shared_ptr<U> where U can be anything
+template <typename T>
+using is_shared_ptr = is_instantiation<std::shared_ptr, T>;
+
+/// Check if T looks like an input iterator
+template <typename T, typename = void>
+struct is_input_iterator : std::false_type {};
+template <typename T>
+struct is_input_iterator<T,
+                         void_t<decltype(*std::declval<T &>()), decltype(++std::declval<T &>())>>
+    : std::true_type {};
+
+template <typename T>
+using is_function_pointer
+    = bool_constant<std::is_pointer<T>::value
+                    && std::is_function<typename std::remove_pointer<T>::type>::value>;
+
+template <typename F>
+struct strip_function_object {
+    // If you are encountering an
+    // 'error: name followed by "::" must be a class or namespace name'
+    // with the Intel compiler and a noexcept function here,
+    // try to use noexcept(true) instead of plain noexcept.
+    using type = typename remove_class<decltype(&F::operator())>::type;
+};
+
+// Extracts the function signature from a function, function pointer or lambda.
+template <typename Function, typename F = remove_reference_t<Function>>
+using function_signature_t = conditional_t<
+    std::is_function<F>::value,
+    F,
+    typename conditional_t<std::is_pointer<F>::value || std::is_member_pointer<F>::value,
+                           std::remove_pointer<F>,
+                           strip_function_object<F>>::type>;
+
+/// Returns true if the type looks like a lambda: that is, isn't a function, pointer or member
+/// pointer.  Note that this can catch all sorts of other things, too; this is intended to be used
+/// in a place where passing a lambda makes sense.
+template <typename T>
+using is_lambda = satisfies_none_of<remove_reference_t<T>,
+                                    std::is_function,
+                                    std::is_pointer,
+                                    std::is_member_pointer>;
+
+// [workaround(intel)] Internal error on fold expression
+/// Apply a function over each element of a parameter pack
+#if defined(__cpp_fold_expressions) && !defined(__INTEL_COMPILER)
+// Intel compiler produces an internal error on this fold expression (tested with ICC 19.0.2)
+#    define PYBIND11_EXPAND_SIDE_EFFECTS(PATTERN) (((PATTERN), void()), ...)
+#else
+using expand_side_effects = bool[];
+#    define PYBIND11_EXPAND_SIDE_EFFECTS(PATTERN)                                                 \
+        (void) pybind11::detail::expand_side_effects { ((PATTERN), void(), false)..., false }
+#endif
+
+PYBIND11_NAMESPACE_END(detail)
+
+/// C++ bindings of builtin Python exceptions
+class PYBIND11_EXPORT_EXCEPTION builtin_exception : public std::runtime_error {
+public:
+    using std::runtime_error::runtime_error;
+    /// Set the error using the Python C API
+    virtual void set_error() const = 0;
+};
+
+#define PYBIND11_RUNTIME_EXCEPTION(name, type)                                                    \
+    class PYBIND11_EXPORT_EXCEPTION name : public builtin_exception {                             \
+    public:                                                                                       \
+        using builtin_exception::builtin_exception;                                               \
+        name() : name("") {}                                                                      \
+        void set_error() const override { PyErr_SetString(type, what()); }                        \
+    };
+
+PYBIND11_RUNTIME_EXCEPTION(stop_iteration, PyExc_StopIteration)
+PYBIND11_RUNTIME_EXCEPTION(index_error, PyExc_IndexError)
+PYBIND11_RUNTIME_EXCEPTION(key_error, PyExc_KeyError)
+PYBIND11_RUNTIME_EXCEPTION(value_error, PyExc_ValueError)
+PYBIND11_RUNTIME_EXCEPTION(type_error, PyExc_TypeError)
+PYBIND11_RUNTIME_EXCEPTION(buffer_error, PyExc_BufferError)
+PYBIND11_RUNTIME_EXCEPTION(import_error, PyExc_ImportError)
+PYBIND11_RUNTIME_EXCEPTION(attribute_error, PyExc_AttributeError)
+PYBIND11_RUNTIME_EXCEPTION(cast_error, PyExc_RuntimeError) /// Thrown when pybind11::cast or
+                                                           /// handle::call fail due to a type
+                                                           /// casting error
+PYBIND11_RUNTIME_EXCEPTION(reference_cast_error, PyExc_RuntimeError) /// Used internally
+
+[[noreturn]] PYBIND11_NOINLINE void pybind11_fail(const char *reason) {
+    assert(!PyErr_Occurred());
+    throw std::runtime_error(reason);
+}
+[[noreturn]] PYBIND11_NOINLINE void pybind11_fail(const std::string &reason) {
+    assert(!PyErr_Occurred());
+    throw std::runtime_error(reason);
+}
+
+template <typename T, typename SFINAE = void>
+struct format_descriptor {};
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+// Returns the index of the given type in the type char array below, and in the list in numpy.h
+// The order here is: bool; 8 ints ((signed,unsigned)x(8,16,32,64)bits); float,double,long double;
+// complex float,double,long double.  Note that the long double types only participate when long
+// double is actually longer than double (it isn't under MSVC).
+// NB: not only the string below but also complex.h and numpy.h rely on this order.
+template <typename T, typename SFINAE = void>
+struct is_fmt_numeric {
+    static constexpr bool value = false;
+};
+template <typename T>
+struct is_fmt_numeric<T, enable_if_t<std::is_arithmetic<T>::value>> {
+    static constexpr bool value = true;
+    static constexpr int index
+        = std::is_same<T, bool>::value
+              ? 0
+              : 1
+                    + (std::is_integral<T>::value
+                           ? detail::log2(sizeof(T)) * 2 + std::is_unsigned<T>::value
+                           : 8
+                                 + (std::is_same<T, double>::value        ? 1
+                                    : std::is_same<T, long double>::value ? 2
+                                                                          : 0));
+};
+PYBIND11_NAMESPACE_END(detail)
+
+template <typename T>
+struct format_descriptor<T, detail::enable_if_t<std::is_arithmetic<T>::value>> {
+    static constexpr const char c = "?bBhHiIqQfdg"[detail::is_fmt_numeric<T>::index];
+    static constexpr const char value[2] = {c, '\0'};
+    static std::string format() { return std::string(1, c); }
+};
+
+#if !defined(PYBIND11_CPP17)
+
+template <typename T>
+constexpr const char
+    format_descriptor<T, detail::enable_if_t<std::is_arithmetic<T>::value>>::value[2];
+
+#endif
+
+/// RAII wrapper that temporarily clears any Python error state
+struct error_scope {
+    PyObject *type, *value, *trace;
+    error_scope() { PyErr_Fetch(&type, &value, &trace); }
+    error_scope(const error_scope &) = delete;
+    error_scope &operator=(const error_scope &) = delete;
+    ~error_scope() { PyErr_Restore(type, value, trace); }
+};
+
+/// Dummy destructor wrapper that can be used to expose classes with a private destructor
+struct nodelete {
+    template <typename T>
+    void operator()(T *) {}
+};
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+template <typename... Args>
+struct overload_cast_impl {
+    template <typename Return>
+    constexpr auto operator()(Return (*pf)(Args...)) const noexcept -> decltype(pf) {
+        return pf;
+    }
+
+    template <typename Return, typename Class>
+    constexpr auto operator()(Return (Class::*pmf)(Args...), std::false_type = {}) const noexcept
+        -> decltype(pmf) {
+        return pmf;
+    }
+
+    template <typename Return, typename Class>
+    constexpr auto operator()(Return (Class::*pmf)(Args...) const, std::true_type) const noexcept
+        -> decltype(pmf) {
+        return pmf;
+    }
+};
+PYBIND11_NAMESPACE_END(detail)
+
+// overload_cast requires variable templates: C++14
+#if defined(PYBIND11_CPP14)
+#    define PYBIND11_OVERLOAD_CAST 1
+/// Syntax sugar for resolving overloaded function pointers:
+///  - regular: static_cast<Return (Class::*)(Arg0, Arg1, Arg2)>(&Class::func)
+///  - sweet:   overload_cast<Arg0, Arg1, Arg2>(&Class::func)
+template <typename... Args>
+static constexpr detail::overload_cast_impl<Args...> overload_cast{};
+#endif
+
+/// Const member function selector for overload_cast
+///  - regular: static_cast<Return (Class::*)(Arg) const>(&Class::func)
+///  - sweet:   overload_cast<Arg>(&Class::func, const_)
+static constexpr auto const_ = std::true_type{};
+
+#if !defined(PYBIND11_CPP14) // no overload_cast: providing something that static_assert-fails:
+template <typename... Args>
+struct overload_cast {
+    static_assert(detail::deferred_t<std::false_type, Args...>::value,
+                  "pybind11::overload_cast<...> requires compiling in C++14 mode");
+};
+#endif // overload_cast
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+// Adaptor for converting arbitrary container arguments into a vector; implicitly convertible from
+// any standard container (or C-style array) supporting std::begin/std::end, any singleton
+// arithmetic type (if T is arithmetic), or explicitly constructible from an iterator pair.
+template <typename T>
+class any_container {
+    std::vector<T> v;
+
+public:
+    any_container() = default;
+
+    // Can construct from a pair of iterators
+    template <typename It, typename = enable_if_t<is_input_iterator<It>::value>>
+    any_container(It first, It last) : v(first, last) {}
+
+    // Implicit conversion constructor from any arbitrary container type
+    // with values convertible to T
+    template <typename Container,
+              typename = enable_if_t<
+                  std::is_convertible<decltype(*std::begin(std::declval<const Container &>())),
+                                      T>::value>>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    any_container(const Container &c) : any_container(std::begin(c), std::end(c)) {}
+
+    // initializer_list's aren't deducible, so don't get matched by the above template;
+    // we need this to explicitly allow implicit conversion from one:
+    template <typename TIn, typename = enable_if_t<std::is_convertible<TIn, T>::value>>
+    any_container(const std::initializer_list<TIn> &c) : any_container(c.begin(), c.end()) {}
+
+    // Avoid copying if given an rvalue vector of the correct type.
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    any_container(std::vector<T> &&v) : v(std::move(v)) {}
+
+    // Moves the vector out of an rvalue any_container
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    operator std::vector<T> &&() && { return std::move(v); }
+
+    // Dereferencing obtains a reference to the underlying vector
+    std::vector<T> &operator*() { return v; }
+    const std::vector<T> &operator*() const { return v; }
+
+    // -> lets you call methods on the underlying vector
+    std::vector<T> *operator->() { return &v; }
+    const std::vector<T> *operator->() const { return &v; }
+};
+
+// Forward-declaration; see detail/class.h
+std::string get_fully_qualified_tp_name(PyTypeObject *);
+
+template <typename T>
+inline static std::shared_ptr<T>
+try_get_shared_from_this(std::enable_shared_from_this<T> *holder_value_ptr) {
+// Pre C++17, this code path exploits undefined behavior, but is known to work on many platforms.
+// Use at your own risk!
+// See also https://en.cppreference.com/w/cpp/memory/enable_shared_from_this, and in particular
+// the `std::shared_ptr<Good> gp1 = not_so_good.getptr();` and `try`-`catch` parts of the example.
+#if defined(__cpp_lib_enable_shared_from_this) && (!defined(_MSC_VER) || _MSC_VER >= 1912)
+    return holder_value_ptr->weak_from_this().lock();
+#else
+    try {
+        return holder_value_ptr->shared_from_this();
+    } catch (const std::bad_weak_ptr &) {
+        return nullptr;
+    }
+#endif
+}
+
+// For silencing "unused" compiler warnings in special situations.
+template <typename... Args>
+#if defined(_MSC_VER) && _MSC_VER < 1920 // MSVC 2017
+constexpr
+#endif
+    inline void
+    silence_unused_warnings(Args &&...) {
+}
+
+// MSVC warning C4100: Unreferenced formal parameter
+#if defined(_MSC_VER) && _MSC_VER <= 1916
+#    define PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(...)                                         \
+        detail::silence_unused_warnings(__VA_ARGS__)
+#else
+#    define PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(...)
+#endif
+
+// GCC -Wunused-but-set-parameter  All GCC versions (as of July 2021).
+#if defined(__GNUG__) && !defined(__clang__) && !defined(__INTEL_COMPILER)
+#    define PYBIND11_WORKAROUND_INCORRECT_GCC_UNUSED_BUT_SET_PARAMETER(...)                       \
+        detail::silence_unused_warnings(__VA_ARGS__)
+#else
+#    define PYBIND11_WORKAROUND_INCORRECT_GCC_UNUSED_BUT_SET_PARAMETER(...)
+#endif
+
+#if defined(__clang__)                                                                            \
+    && (defined(__apple_build_version__) /* AppleClang 13.0.0.13000029 was the only data point    \
+                                            available. */                                         \
+        || (__clang_major__ >= 7                                                                  \
+            && __clang_major__ <= 12) /* Clang 3, 5, 13, 14, 15 do not generate the warning. */   \
+    )
+#    define PYBIND11_DETECTED_CLANG_WITH_MISLEADING_CALL_STD_MOVE_EXPLICITLY_WARNING
+// Example:
+// tests/test_kwargs_and_defaults.cpp:46:68: error: local variable 'args' will be copied despite
+// being returned by name [-Werror,-Wreturn-std-move]
+//     m.def("args_function", [](py::args args) -> py::tuple { return args; });
+//                                                                    ^~~~
+// test_kwargs_and_defaults.cpp:46:68: note: call 'std::move' explicitly to avoid copying
+//     m.def("args_function", [](py::args args) -> py::tuple { return args; });
+//                                                                    ^~~~
+//                                                                    std::move(args)
+#endif
+
+// Pybind offers detailed error messages by default for all builts that are debug (through the
+// negation of ndebug). This can also be manually enabled by users, for any builds, through
+// defining PYBIND11_DETAILED_ERROR_MESSAGES.
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES) && !defined(NDEBUG)
+#    define PYBIND11_DETAILED_ERROR_MESSAGES
+#endif
+
+PYBIND11_NAMESPACE_END(detail)
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)
diff --git a/Patches/pybind11/include/pybind11/pybind11.h b/Patches/pybind11/include/pybind11/pybind11.h
deleted file mode 100644
index d449eff8..00000000
--- a/Patches/pybind11/include/pybind11/pybind11.h
+++ /dev/null
@@ -1,1838 +0,0 @@
-/*
-    pybind11/pybind11.h: Main header file of the C++11 python
-    binding generator library
-
-    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
-
-    All rights reserved. Use of this source code is governed by a
-    BSD-style license that can be found in the LICENSE file.
-*/
-
-#pragma once
-
-#if defined(_MSC_VER)
-#  pragma warning(push)
-#  pragma warning(disable: 4100) // warning C4100: Unreferenced formal parameter
-#  pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
-#  pragma warning(disable: 4512) // warning C4512: Assignment operator was implicitly defined as deleted
-#  pragma warning(disable: 4800) // warning C4800: 'int': forcing value to bool 'true' or 'false' (performance warning)
-#  pragma warning(disable: 4996) // warning C4996: The POSIX name for this item is deprecated. Instead, use the ISO C and C++ conformant name
-#  pragma warning(disable: 4702) // warning C4702: unreachable code
-#  pragma warning(disable: 4522) // warning C4522: multiple assignment operators specified
-#elif defined(__INTEL_COMPILER)
-#  pragma warning(push)
-#  pragma warning(disable: 68)    // integer conversion resulted in a change of sign
-#  pragma warning(disable: 186)   // pointless comparison of unsigned integer with zero
-#  pragma warning(disable: 878)   // incompatible exception specifications
-#  pragma warning(disable: 1334)  // the "template" keyword used for syntactic disambiguation may only be used within a template
-#  pragma warning(disable: 1682)  // implicit conversion of a 64-bit integral type to a smaller integral type (potential portability problem)
-#  pragma warning(disable: 1875)  // offsetof applied to non-POD (Plain Old Data) types is nonstandard
-#  pragma warning(disable: 2196)  // warning #2196: routine is both "inline" and "noinline"
-#elif defined(__GNUG__) && !defined(__clang__)
-#  pragma GCC diagnostic push
-#  pragma GCC diagnostic ignored "-Wunused-but-set-parameter"
-#  pragma GCC diagnostic ignored "-Wunused-but-set-variable"
-#  pragma GCC diagnostic ignored "-Wmissing-field-initializers"
-#  pragma GCC diagnostic ignored "-Wstrict-aliasing"
-#  pragma GCC diagnostic ignored "-Wattributes"
-#  if __GNUC__ >= 7
-#    pragma GCC diagnostic ignored "-Wnoexcept-type"
-#  endif
-#endif
-
-#include "attr.h"
-#include "options.h"
-#include "detail/class.h"
-#include "detail/init.h"
-
-NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
-
-/// Wraps an arbitrary C++ function/method/lambda function/.. into a callable Python object
-class cpp_function : public function {
-public:
-    cpp_function() { }
-
-    /// Construct a cpp_function from a vanilla function pointer
-    template <typename Return, typename... Args, typename... Extra>
-    cpp_function(Return (*f)(Args...), const Extra&... extra) {
-        initialize(f, f, extra...);
-    }
-
-    /// Construct a cpp_function from a lambda function (possibly with internal state)
-    template <typename Func, typename... Extra,
-              typename = detail::enable_if_t<detail::is_lambda<Func>::value>>
-    cpp_function(Func &&f, const Extra&... extra) {
-        initialize(std::forward<Func>(f),
-                   (detail::function_signature_t<Func> *) nullptr, extra...);
-    }
-
-    /// Construct a cpp_function from a class method (non-const)
-    template <typename Return, typename Class, typename... Arg, typename... Extra>
-    cpp_function(Return (Class::*f)(Arg...), const Extra&... extra) {
-        initialize([f](Class *c, Arg... args) -> Return { return (c->*f)(args...); },
-                   (Return (*) (Class *, Arg...)) nullptr, extra...);
-    }
-
-    /// Construct a cpp_function from a class method (const)
-    template <typename Return, typename Class, typename... Arg, typename... Extra>
-    cpp_function(Return (Class::*f)(Arg...) const, const Extra&... extra) {
-        initialize([f](const Class *c, Arg... args) -> Return { return (c->*f)(args...); },
-                   (Return (*)(const Class *, Arg ...)) nullptr, extra...);
-    }
-
-    /// Return the function name
-    object name() const { return attr("__name__"); }
-
-protected:
-    /// Space optimization: don't inline this frequently instantiated fragment
-    PYBIND11_NOINLINE detail::function_record *make_function_record() {
-        return new detail::function_record();
-    }
-
-    /// Special internal constructor for functors, lambda functions, etc.
-    template <typename Func, typename Return, typename... Args, typename... Extra>
-    void initialize(Func &&f, Return (*)(Args...), const Extra&... extra) {
-
-        struct capture { detail::remove_reference_t<Func> f; };
-
-        /* Store the function including any extra state it might have (e.g. a lambda capture object) */
-        auto rec = make_function_record();
-
-        /* Store the capture object directly in the function record if there is enough space */
-        if (sizeof(capture) <= sizeof(rec->data)) {
-            /* Without these pragmas, GCC warns that there might not be
-               enough space to use the placement new operator. However, the
-               'if' statement above ensures that this is the case. */
-#if defined(__GNUG__) && !defined(__clang__) && __GNUC__ >= 6
-#  pragma GCC diagnostic push
-#  pragma GCC diagnostic ignored "-Wplacement-new"
-#endif
-            new ((capture *) &rec->data) capture { std::forward<Func>(f) };
-#if defined(__GNUG__) && !defined(__clang__) && __GNUC__ >= 6
-#  pragma GCC diagnostic pop
-#endif
-            if (!std::is_trivially_destructible<Func>::value)
-                rec->free_data = [](detail::function_record *r) { ((capture *) &r->data)->~capture(); };
-        } else {
-            rec->data[0] = new capture { std::forward<Func>(f) };
-            rec->free_data = [](detail::function_record *r) { delete ((capture *) r->data[0]); };
-        }
-
-        /* Type casters for the function arguments and return value */
-        using cast_in = detail::argument_loader<Args...>;
-        using cast_out = detail::make_caster<
-            detail::conditional_t<std::is_void<Return>::value, detail::void_type, Return>
-        >;
-
-        static_assert(detail::expected_num_args<Extra...>(sizeof...(Args), cast_in::has_args, cast_in::has_kwargs),
-                      "The number of argument annotations does not match the number of function arguments");
-
-        /* Dispatch code which converts function arguments and performs the actual function call */
-        rec->impl = [](detail::function_call &call) -> handle {
-            cast_in args_converter;
-
-            /* Try to cast the function arguments into the C++ domain */
-            if (!args_converter.load_args(call))
-                return PYBIND11_TRY_NEXT_OVERLOAD;
-
-            /* Invoke call policy pre-call hook */
-            detail::process_attributes<Extra...>::precall(call);
-
-            /* Get a pointer to the capture object */
-            auto data = (sizeof(capture) <= sizeof(call.func.data)
-                         ? &call.func.data : call.func.data[0]);
-            capture *cap = const_cast<capture *>(reinterpret_cast<const capture *>(data));
-
-            /* Override policy for rvalues -- usually to enforce rvp::move on an rvalue */
-            const auto policy = detail::return_value_policy_override<Return>::policy(call.func.policy);
-
-            /* Function scope guard -- defaults to the compile-to-nothing `void_type` */
-            using Guard = detail::extract_guard_t<Extra...>;
-
-            /* Perform the function call */
-            handle result = cast_out::cast(
-                std::move(args_converter).template call<Return, Guard>(cap->f), policy, call.parent);
-
-            /* Invoke call policy post-call hook */
-            detail::process_attributes<Extra...>::postcall(call, result);
-
-            return result;
-        };
-
-        /* Process any user-provided function attributes */
-        detail::process_attributes<Extra...>::init(extra..., rec);
-
-        /* Generate a readable signature describing the function's arguments and return value types */
-        using detail::descr; using detail::_;
-        PYBIND11_DESCR signature = _("(") + cast_in::arg_names() + _(") -> ") + cast_out::name();
-
-        /* Register the function with Python from generic (non-templated) code */
-        initialize_generic(rec, signature.text(), signature.types(), sizeof...(Args));
-
-        if (cast_in::has_args) rec->has_args = true;
-        if (cast_in::has_kwargs) rec->has_kwargs = true;
-
-        /* Stash some additional information used by an important optimization in 'functional.h' */
-        using FunctionType = Return (*)(Args...);
-        constexpr bool is_function_ptr =
-            std::is_convertible<Func, FunctionType>::value &&
-            sizeof(capture) == sizeof(void *);
-        if (is_function_ptr) {
-            rec->is_stateless = true;
-            rec->data[1] = const_cast<void *>(reinterpret_cast<const void *>(&typeid(FunctionType)));
-        }
-    }
-
-    /// Register a function call with Python (generic non-templated code goes here)
-    void initialize_generic(detail::function_record *rec, const char *text,
-                            const std::type_info *const *types, size_t args) {
-
-        /* Create copies of all referenced C-style strings */
-        rec->name = strdup(rec->name ? rec->name : "");
-        if (rec->doc) rec->doc = strdup(rec->doc);
-        for (auto &a: rec->args) {
-            if (a.name)
-                a.name = strdup(a.name);
-            if (a.descr)
-                a.descr = strdup(a.descr);
-            else if (a.value)
-                a.descr = strdup(a.value.attr("__repr__")().cast<std::string>().c_str());
-        }
-
-        rec->is_constructor = !strcmp(rec->name, "__init__") || !strcmp(rec->name, "__setstate__");
-
-#if !defined(NDEBUG) && !defined(PYBIND11_DISABLE_NEW_STYLE_INIT_WARNING)
-        if (rec->is_constructor && !rec->is_new_style_constructor) {
-            const auto class_name = std::string(((PyTypeObject *) rec->scope.ptr())->tp_name);
-            const auto func_name = std::string(rec->name);
-            PyErr_WarnEx(
-                PyExc_FutureWarning,
-                ("pybind11-bound class '" + class_name + "' is using an old-style "
-                 "placement-new '" + func_name + "' which has been deprecated. See "
-                 "the upgrade guide in pybind11's docs. This message is only visible "
-                 "when compiled in debug mode.").c_str(), 0
-            );
-        }
-#endif
-
-        /* Generate a proper function signature */
-        std::string signature;
-        size_t type_depth = 0, char_index = 0, type_index = 0, arg_index = 0;
-        while (true) {
-            char c = text[char_index++];
-            if (c == '\0')
-                break;
-
-            if (c == '{') {
-                // Write arg name for everything except *args, **kwargs and return type.
-                if (type_depth == 0 && text[char_index] != '*' && arg_index < args) {
-                    if (!rec->args.empty() && rec->args[arg_index].name) {
-                        signature += rec->args[arg_index].name;
-                    } else if (arg_index == 0 && rec->is_method) {
-                        signature += "self";
-                    } else {
-                        signature += "arg" + std::to_string(arg_index - (rec->is_method ? 1 : 0));
-                    }
-                    signature += ": ";
-                }
-                ++type_depth;
-            } else if (c == '}') {
-                --type_depth;
-                if (type_depth == 0) {
-                    if (arg_index < rec->args.size() && rec->args[arg_index].descr) {
-                        signature += "=";
-                        signature += rec->args[arg_index].descr;
-                    }
-                    arg_index++;
-                }
-            } else if (c == '%') {
-                const std::type_info *t = types[type_index++];
-                if (!t)
-                    pybind11_fail("Internal error while parsing type signature (1)");
-                if (auto tinfo = detail::get_type_info(*t)) {
-#if defined(PYPY_VERSION)
-                    signature += handle((PyObject *) tinfo->type)
-                                     .attr("__module__")
-                                     .cast<std::string>() + ".";
-#endif
-                    signature += tinfo->type->tp_name;
-                } else if (rec->is_new_style_constructor && arg_index == 0) {
-                    // A new-style `__init__` takes `self` as `value_and_holder`.
-                    // Rewrite it to the proper class type.
-#if defined(PYPY_VERSION)
-                    signature += rec->scope.attr("__module__").cast<std::string>() + ".";
-#endif
-                    signature += ((PyTypeObject *) rec->scope.ptr())->tp_name;
-                } else {
-                    std::string tname(t->name());
-                    detail::clean_type_id(tname);
-                    signature += tname;
-                }
-            } else {
-                signature += c;
-            }
-        }
-        if (type_depth != 0 || types[type_index] != nullptr)
-            pybind11_fail("Internal error while parsing type signature (2)");
-
-        #if !defined(PYBIND11_CONSTEXPR_DESCR)
-            delete[] types;
-            delete[] text;
-        #endif
-
-#if PY_MAJOR_VERSION < 3
-        if (strcmp(rec->name, "__next__") == 0) {
-            std::free(rec->name);
-            rec->name = strdup("next");
-        } else if (strcmp(rec->name, "__bool__") == 0) {
-            std::free(rec->name);
-            rec->name = strdup("__nonzero__");
-        }
-#endif
-        rec->signature = strdup(signature.c_str());
-        rec->args.shrink_to_fit();
-        rec->nargs = (std::uint16_t) args;
-
-        if (rec->sibling && PYBIND11_INSTANCE_METHOD_CHECK(rec->sibling.ptr()))
-            rec->sibling = PYBIND11_INSTANCE_METHOD_GET_FUNCTION(rec->sibling.ptr());
-
-        detail::function_record *chain = nullptr, *chain_start = rec;
-        if (rec->sibling) {
-            if (PyCFunction_Check(rec->sibling.ptr())) {
-                auto rec_capsule = reinterpret_borrow<capsule>(PyCFunction_GET_SELF(rec->sibling.ptr()));
-                chain = (detail::function_record *) rec_capsule;
-                /* Never append a method to an overload chain of a parent class;
-                   instead, hide the parent's overloads in this case */
-                if (!chain->scope.is(rec->scope))
-                    chain = nullptr;
-            }
-            // Don't trigger for things like the default __init__, which are wrapper_descriptors that we are intentionally replacing
-            else if (!rec->sibling.is_none() && rec->name[0] != '_')
-                pybind11_fail("Cannot overload existing non-function object \"" + std::string(rec->name) +
-                        "\" with a function of the same name");
-        }
-
-        if (!chain) {
-            /* No existing overload was found, create a new function object */
-            rec->def = new PyMethodDef();
-            std::memset(rec->def, 0, sizeof(PyMethodDef));
-            rec->def->ml_name = rec->name;
-            rec->def->ml_meth = reinterpret_cast<PyCFunction>(*dispatcher);
-            rec->def->ml_flags = METH_VARARGS | METH_KEYWORDS;
-
-            capsule rec_capsule(rec, [](void *ptr) {
-                destruct((detail::function_record *) ptr);
-            });
-
-            object scope_module;
-            if (rec->scope) {
-                if (hasattr(rec->scope, "__module__")) {
-                    scope_module = rec->scope.attr("__module__");
-                } else if (hasattr(rec->scope, "__name__")) {
-                    scope_module = rec->scope.attr("__name__");
-                }
-            }
-
-            m_ptr = PyCFunction_NewEx(rec->def, rec_capsule.ptr(), scope_module.ptr());
-            if (!m_ptr)
-                pybind11_fail("cpp_function::cpp_function(): Could not allocate function object");
-        } else {
-            /* Append at the end of the overload chain */
-            m_ptr = rec->sibling.ptr();
-            inc_ref();
-            chain_start = chain;
-            if (chain->is_method != rec->is_method)
-                pybind11_fail("overloading a method with both static and instance methods is not supported; "
-                    #if defined(NDEBUG)
-                        "compile in debug mode for more details"
-                    #else
-                        "error while attempting to bind " + std::string(rec->is_method ? "instance" : "static") + " method " +
-                        std::string(pybind11::str(rec->scope.attr("__name__"))) + "." + std::string(rec->name) + signature
-                    #endif
-                );
-            while (chain->next)
-                chain = chain->next;
-            chain->next = rec;
-        }
-
-        std::string signatures;
-        int index = 0;
-        /* Create a nice pydoc rec including all signatures and
-           docstrings of the functions in the overload chain */
-        if (chain && options::show_function_signatures()) {
-            // First a generic signature
-            signatures += rec->name;
-            signatures += "(*args, **kwargs)\n";
-            signatures += "Overloaded function.\n\n";
-        }
-        // Then specific overload signatures
-        bool first_user_def = true;
-        for (auto it = chain_start; it != nullptr; it = it->next) {
-            if (options::show_function_signatures()) {
-                if (index > 0) signatures += "\n";
-                if (chain)
-                    signatures += std::to_string(++index) + ". ";
-                signatures += rec->name;
-                signatures += it->signature;
-                signatures += "\n";
-            }
-            if (it->doc && strlen(it->doc) > 0 && options::show_user_defined_docstrings()) {
-                // If we're appending another docstring, and aren't printing function signatures, we
-                // need to append a newline first:
-                if (!options::show_function_signatures()) {
-                    if (first_user_def) first_user_def = false;
-                    else signatures += "\n";
-                }
-                if (options::show_function_signatures()) signatures += "\n";
-                signatures += it->doc;
-                if (options::show_function_signatures()) signatures += "\n";
-            }
-        }
-
-        /* Install docstring */
-        PyCFunctionObject *func = (PyCFunctionObject *) m_ptr;
-        if (func->m_ml->ml_doc)
-            std::free(const_cast<char *>(func->m_ml->ml_doc));
-        func->m_ml->ml_doc = strdup(signatures.c_str());
-
-        if (rec->is_method) {
-            m_ptr = PYBIND11_INSTANCE_METHOD_NEW(m_ptr, rec->scope.ptr());
-            if (!m_ptr)
-                pybind11_fail("cpp_function::cpp_function(): Could not allocate instance method object");
-            Py_DECREF(func);
-        }
-    }
-
-    /// When a cpp_function is GCed, release any memory allocated by pybind11
-    static void destruct(detail::function_record *rec) {
-        while (rec) {
-            detail::function_record *next = rec->next;
-            if (rec->free_data)
-                rec->free_data(rec);
-            std::free((char *) rec->name);
-            std::free((char *) rec->doc);
-            std::free((char *) rec->signature);
-            for (auto &arg: rec->args) {
-                std::free(const_cast<char *>(arg.name));
-                std::free(const_cast<char *>(arg.descr));
-                arg.value.dec_ref();
-            }
-            if (rec->def) {
-                std::free(const_cast<char *>(rec->def->ml_doc));
-                delete rec->def;
-            }
-            delete rec;
-            rec = next;
-        }
-    }
-
-    /// Main dispatch logic for calls to functions bound using pybind11
-    static PyObject *dispatcher(PyObject *self, PyObject *args_in, PyObject *kwargs_in) {
-        using namespace detail;
-
-        /* Iterator over the list of potentially admissible overloads */
-        function_record *overloads = (function_record *) PyCapsule_GetPointer(self, nullptr),
-                        *it = overloads;
-
-        /* Need to know how many arguments + keyword arguments there are to pick the right overload */
-        const size_t n_args_in = (size_t) PyTuple_GET_SIZE(args_in);
-
-        handle parent = n_args_in > 0 ? PyTuple_GET_ITEM(args_in, 0) : nullptr,
-               result = PYBIND11_TRY_NEXT_OVERLOAD;
-
-        auto self_value_and_holder = value_and_holder();
-        if (overloads->is_constructor) {
-            const auto tinfo = get_type_info((PyTypeObject *) overloads->scope.ptr());
-            const auto pi = reinterpret_cast<instance *>(parent.ptr());
-            self_value_and_holder = pi->get_value_and_holder(tinfo, false);
-
-            if (!self_value_and_holder.type || !self_value_and_holder.inst) {
-                PyErr_SetString(PyExc_TypeError, "__init__(self, ...) called with invalid `self` argument");
-                return nullptr;
-            }
-
-            // If this value is already registered it must mean __init__ is invoked multiple times;
-            // we really can't support that in C++, so just ignore the second __init__.
-            if (self_value_and_holder.instance_registered())
-                return none().release().ptr();
-        }
-
-        try {
-            // We do this in two passes: in the first pass, we load arguments with `convert=false`;
-            // in the second, we allow conversion (except for arguments with an explicit
-            // py::arg().noconvert()).  This lets us prefer calls without conversion, with
-            // conversion as a fallback.
-            std::vector<function_call> second_pass;
-
-            // However, if there are no overloads, we can just skip the no-convert pass entirely
-            const bool overloaded = it != nullptr && it->next != nullptr;
-
-            for (; it != nullptr; it = it->next) {
-
-                /* For each overload:
-                   1. Copy all positional arguments we were given, also checking to make sure that
-                      named positional arguments weren't *also* specified via kwarg.
-                   2. If we weren't given enough, try to make up the omitted ones by checking
-                      whether they were provided by a kwarg matching the `py::arg("name")` name.  If
-                      so, use it (and remove it from kwargs; if not, see if the function binding
-                      provided a default that we can use.
-                   3. Ensure that either all keyword arguments were "consumed", or that the function
-                      takes a kwargs argument to accept unconsumed kwargs.
-                   4. Any positional arguments still left get put into a tuple (for args), and any
-                      leftover kwargs get put into a dict.
-                   5. Pack everything into a vector; if we have py::args or py::kwargs, they are an
-                      extra tuple or dict at the end of the positional arguments.
-                   6. Call the function call dispatcher (function_record::impl)
-
-                   If one of these fail, move on to the next overload and keep trying until we get a
-                   result other than PYBIND11_TRY_NEXT_OVERLOAD.
-                 */
-
-                function_record &func = *it;
-                size_t pos_args = func.nargs;    // Number of positional arguments that we need
-                if (func.has_args) --pos_args;   // (but don't count py::args
-                if (func.has_kwargs) --pos_args; //  or py::kwargs)
-
-                if (!func.has_args && n_args_in > pos_args)
-                    continue; // Too many arguments for this overload
-
-                if (n_args_in < pos_args && func.args.size() < pos_args)
-                    continue; // Not enough arguments given, and not enough defaults to fill in the blanks
-
-                function_call call(func, parent);
-
-                size_t args_to_copy = std::min(pos_args, n_args_in);
-                size_t args_copied = 0;
-
-                // 0. Inject new-style `self` argument
-                if (func.is_new_style_constructor) {
-                    // The `value` may have been preallocated by an old-style `__init__`
-                    // if it was a preceding candidate for overload resolution.
-                    if (self_value_and_holder)
-                        self_value_and_holder.type->dealloc(self_value_and_holder);
-
-                    call.init_self = PyTuple_GET_ITEM(args_in, 0);
-                    call.args.push_back(reinterpret_cast<PyObject *>(&self_value_and_holder));
-                    call.args_convert.push_back(false);
-                    ++args_copied;
-                }
-
-                // 1. Copy any position arguments given.
-                bool bad_arg = false;
-                for (; args_copied < args_to_copy; ++args_copied) {
-                    argument_record *arg_rec = args_copied < func.args.size() ? &func.args[args_copied] : nullptr;
-                    if (kwargs_in && arg_rec && arg_rec->name && PyDict_GetItemString(kwargs_in, arg_rec->name)) {
-                        bad_arg = true;
-                        break;
-                    }
-
-                    handle arg(PyTuple_GET_ITEM(args_in, args_copied));
-                    if (arg_rec && !arg_rec->none && arg.is_none()) {
-                        bad_arg = true;
-                        break;
-                    }
-                    call.args.push_back(arg);
-                    call.args_convert.push_back(arg_rec ? arg_rec->convert : true);
-                }
-                if (bad_arg)
-                    continue; // Maybe it was meant for another overload (issue #688)
-
-                // We'll need to copy this if we steal some kwargs for defaults
-                dict kwargs = reinterpret_borrow<dict>(kwargs_in);
-
-                // 2. Check kwargs and, failing that, defaults that may help complete the list
-                if (args_copied < pos_args) {
-                    bool copied_kwargs = false;
-
-                    for (; args_copied < pos_args; ++args_copied) {
-                        const auto &arg = func.args[args_copied];
-
-                        handle value;
-                        if (kwargs_in && arg.name)
-                            value = PyDict_GetItemString(kwargs.ptr(), arg.name);
-
-                        if (value) {
-                            // Consume a kwargs value
-                            if (!copied_kwargs) {
-                                kwargs = reinterpret_steal<dict>(PyDict_Copy(kwargs.ptr()));
-                                copied_kwargs = true;
-                            }
-                            PyDict_DelItemString(kwargs.ptr(), arg.name);
-                        } else if (arg.value) {
-                            value = arg.value;
-                        }
-
-                        if (value) {
-                            call.args.push_back(value);
-                            call.args_convert.push_back(arg.convert);
-                        }
-                        else
-                            break;
-                    }
-
-                    if (args_copied < pos_args)
-                        continue; // Not enough arguments, defaults, or kwargs to fill the positional arguments
-                }
-
-                // 3. Check everything was consumed (unless we have a kwargs arg)
-                if (kwargs && kwargs.size() > 0 && !func.has_kwargs)
-                    continue; // Unconsumed kwargs, but no py::kwargs argument to accept them
-
-                // 4a. If we have a py::args argument, create a new tuple with leftovers
-                tuple extra_args;
-                if (func.has_args) {
-                    if (args_to_copy == 0) {
-                        // We didn't copy out any position arguments from the args_in tuple, so we
-                        // can reuse it directly without copying:
-                        extra_args = reinterpret_borrow<tuple>(args_in);
-                    } else if (args_copied >= n_args_in) {
-                        extra_args = tuple(0);
-                    } else {
-                        size_t args_size = n_args_in - args_copied;
-                        extra_args = tuple(args_size);
-                        for (size_t i = 0; i < args_size; ++i) {
-                            handle item = PyTuple_GET_ITEM(args_in, args_copied + i);
-                            extra_args[i] = item.inc_ref().ptr();
-                        }
-                    }
-                    call.args.push_back(extra_args);
-                    call.args_convert.push_back(false);
-                }
-
-                // 4b. If we have a py::kwargs, pass on any remaining kwargs
-                if (func.has_kwargs) {
-                    if (!kwargs.ptr())
-                        kwargs = dict(); // If we didn't get one, send an empty one
-                    call.args.push_back(kwargs);
-                    call.args_convert.push_back(false);
-                }
-
-                // 5. Put everything in a vector.  Not technically step 5, we've been building it
-                // in `call.args` all along.
-                #if !defined(NDEBUG)
-                if (call.args.size() != func.nargs || call.args_convert.size() != func.nargs)
-                    pybind11_fail("Internal error: function call dispatcher inserted wrong number of arguments!");
-                #endif
-
-                std::vector<bool> second_pass_convert;
-                if (overloaded) {
-                    // We're in the first no-convert pass, so swap out the conversion flags for a
-                    // set of all-false flags.  If the call fails, we'll swap the flags back in for
-                    // the conversion-allowed call below.
-                    second_pass_convert.resize(func.nargs, false);
-                    call.args_convert.swap(second_pass_convert);
-                }
-
-                // 6. Call the function.
-                try {
-                    loader_life_support guard{};
-                    result = func.impl(call);
-                } catch (reference_cast_error &) {
-                    result = PYBIND11_TRY_NEXT_OVERLOAD;
-                }
-
-                if (result.ptr() != PYBIND11_TRY_NEXT_OVERLOAD)
-                    break;
-
-                if (overloaded) {
-                    // The (overloaded) call failed; if the call has at least one argument that
-                    // permits conversion (i.e. it hasn't been explicitly specified `.noconvert()`)
-                    // then add this call to the list of second pass overloads to try.
-                    for (size_t i = func.is_method ? 1 : 0; i < pos_args; i++) {
-                        if (second_pass_convert[i]) {
-                            // Found one: swap the converting flags back in and store the call for
-                            // the second pass.
-                            call.args_convert.swap(second_pass_convert);
-                            second_pass.push_back(std::move(call));
-                            break;
-                        }
-                    }
-                }
-            }
-
-            if (overloaded && !second_pass.empty() && result.ptr() == PYBIND11_TRY_NEXT_OVERLOAD) {
-                // The no-conversion pass finished without success, try again with conversion allowed
-                for (auto &call : second_pass) {
-                    try {
-                        loader_life_support guard{};
-                        result = call.func.impl(call);
-                    } catch (reference_cast_error &) {
-                        result = PYBIND11_TRY_NEXT_OVERLOAD;
-                    }
-
-                    if (result.ptr() != PYBIND11_TRY_NEXT_OVERLOAD)
-                        break;
-                }
-            }
-        } catch (error_already_set &e) {
-            e.restore();
-            return nullptr;
-        } catch (...) {
-            /* When an exception is caught, give each registered exception
-               translator a chance to translate it to a Python exception
-               in reverse order of registration.
-
-               A translator may choose to do one of the following:
-
-                - catch the exception and call PyErr_SetString or PyErr_SetObject
-                  to set a standard (or custom) Python exception, or
-                - do nothing and let the exception fall through to the next translator, or
-                - delegate translation to the next translator by throwing a new type of exception. */
-
-            auto last_exception = std::current_exception();
-            auto &registered_exception_translators = get_internals().registered_exception_translators;
-            for (auto& translator : registered_exception_translators) {
-                try {
-                    translator(last_exception);
-                } catch (...) {
-                    last_exception = std::current_exception();
-                    continue;
-                }
-                return nullptr;
-            }
-            PyErr_SetString(PyExc_SystemError, "Exception escaped from default exception translator!");
-            return nullptr;
-        }
-
-        auto append_note_if_missing_header_is_suspected = [](std::string &msg) {
-            if (msg.find("std::") != std::string::npos) {
-                msg += "\n\n"
-                       "Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,\n"
-                       "<pybind11/functional.h>, <pybind11/chrono.h>, etc. Some automatic\n"
-                       "conversions are optional and require extra headers to be included\n"
-                       "when compiling your pybind11 module.";
-            }
-        };
-
-        if (result.ptr() == PYBIND11_TRY_NEXT_OVERLOAD) {
-            if (overloads->is_operator)
-                return handle(Py_NotImplemented).inc_ref().ptr();
-
-            std::string msg = std::string(overloads->name) + "(): incompatible " +
-                std::string(overloads->is_constructor ? "constructor" : "function") +
-                " arguments. The following argument types are supported:\n";
-
-            int ctr = 0;
-            for (function_record *it2 = overloads; it2 != nullptr; it2 = it2->next) {
-                msg += "    "+ std::to_string(++ctr) + ". ";
-
-                bool wrote_sig = false;
-                if (overloads->is_constructor) {
-                    // For a constructor, rewrite `(self: Object, arg0, ...) -> NoneType` as `Object(arg0, ...)`
-                    std::string sig = it2->signature;
-                    size_t start = sig.find('(') + 7; // skip "(self: "
-                    if (start < sig.size()) {
-                        // End at the , for the next argument
-                        size_t end = sig.find(", "), next = end + 2;
-                        size_t ret = sig.rfind(" -> ");
-                        // Or the ), if there is no comma:
-                        if (end >= sig.size()) next = end = sig.find(')');
-                        if (start < end && next < sig.size()) {
-                            msg.append(sig, start, end - start);
-                            msg += '(';
-                            msg.append(sig, next, ret - next);
-                            wrote_sig = true;
-                        }
-                    }
-                }
-                if (!wrote_sig) msg += it2->signature;
-
-                msg += "\n";
-            }
-            msg += "\nInvoked with: ";
-            auto args_ = reinterpret_borrow<tuple>(args_in);
-            bool some_args = false;
-            for (size_t ti = overloads->is_constructor ? 1 : 0; ti < args_.size(); ++ti) {
-                if (!some_args) some_args = true;
-                else msg += ", ";
-                msg += pybind11::repr(args_[ti]);
-            }
-            if (kwargs_in) {
-                auto kwargs = reinterpret_borrow<dict>(kwargs_in);
-                if (kwargs.size() > 0) {
-                    if (some_args) msg += "; ";
-                    msg += "kwargs: ";
-                    bool first = true;
-                    for (auto kwarg : kwargs) {
-                        if (first) first = false;
-                        else msg += ", ";
-                        msg += pybind11::str("{}={!r}").format(kwarg.first, kwarg.second);
-                    }
-                }
-            }
-
-            append_note_if_missing_header_is_suspected(msg);
-            PyErr_SetString(PyExc_TypeError, msg.c_str());
-            return nullptr;
-        } else if (!result) {
-            std::string msg = "Unable to convert function return value to a "
-                              "Python type! The signature was\n\t";
-            msg += it->signature;
-            append_note_if_missing_header_is_suspected(msg);
-            PyErr_SetString(PyExc_TypeError, msg.c_str());
-            return nullptr;
-        } else {
-            if (overloads->is_constructor && !self_value_and_holder.holder_constructed()) {
-                auto *pi = reinterpret_cast<instance *>(parent.ptr());
-                self_value_and_holder.type->init_instance(pi, nullptr);
-            }
-            return result.ptr();
-        }
-    }
-};
-
-/// Wrapper for Python extension modules
-class module : public object {
-public:
-    PYBIND11_OBJECT_DEFAULT(module, object, PyModule_Check)
-
-    /// Create a new top-level Python module with the given name and docstring
-    explicit module(const char *name, const char *doc = nullptr) {
-        if (!options::show_user_defined_docstrings()) doc = nullptr;
-#if PY_MAJOR_VERSION >= 3
-        PyModuleDef *def = new PyModuleDef();
-        std::memset(def, 0, sizeof(PyModuleDef));
-        def->m_name = name;
-        def->m_doc = doc;
-        def->m_size = -1;
-        Py_INCREF(def);
-        m_ptr = PyModule_Create(def);
-#else
-        m_ptr = Py_InitModule3(name, nullptr, doc);
-#endif
-        if (m_ptr == nullptr)
-            pybind11_fail("Internal error in module::module()");
-        inc_ref();
-    }
-
-    /** \rst
-        Create Python binding for a new function within the module scope. ``Func``
-        can be a plain C++ function, a function pointer, or a lambda function. For
-        details on the ``Extra&& ... extra`` argument, see section :ref:`extras`.
-    \endrst */
-    template <typename Func, typename... Extra>
-    module &def(const char *name_, Func &&f, const Extra& ... extra) {
-        cpp_function func(std::forward<Func>(f), name(name_), scope(*this),
-                          sibling(getattr(*this, name_, none())), extra...);
-        // NB: allow overwriting here because cpp_function sets up a chain with the intention of
-        // overwriting (and has already checked internally that it isn't overwriting non-functions).
-        add_object(name_, func, true /* overwrite */);
-        return *this;
-    }
-
-    /** \rst
-        Create and return a new Python submodule with the given name and docstring.
-        This also works recursively, i.e.
-
-        .. code-block:: cpp
-
-            py::module m("example", "pybind11 example plugin");
-            py::module m2 = m.def_submodule("sub", "A submodule of 'example'");
-            py::module m3 = m2.def_submodule("subsub", "A submodule of 'example.sub'");
-    \endrst */
-    module def_submodule(const char *name, const char *doc = nullptr) {
-        std::string full_name = std::string(PyModule_GetName(m_ptr))
-            + std::string(".") + std::string(name);
-        auto result = reinterpret_borrow<module>(PyImport_AddModule(full_name.c_str()));
-        if (doc && options::show_user_defined_docstrings())
-            result.attr("__doc__") = pybind11::str(doc);
-        attr(name) = result;
-        return result;
-    }
-
-    /// Import and return a module or throws `error_already_set`.
-    static module import(const char *name) {
-        PyObject *obj = PyImport_ImportModule(name);
-        if (!obj)
-            throw error_already_set();
-        return reinterpret_steal<module>(obj);
-    }
-
-    /// Reload the module or throws `error_already_set`.
-    void reload() {
-        PyObject *obj = PyImport_ReloadModule(ptr());
-        if (!obj)
-            throw error_already_set();
-        *this = reinterpret_steal<module>(obj);
-    }
-
-    // Adds an object to the module using the given name.  Throws if an object with the given name
-    // already exists.
-    //
-    // overwrite should almost always be false: attempting to overwrite objects that pybind11 has
-    // established will, in most cases, break things.
-    PYBIND11_NOINLINE void add_object(const char *name, handle obj, bool overwrite = false) {
-        if (!overwrite && hasattr(*this, name))
-            pybind11_fail("Error during initialization: multiple incompatible definitions with name \"" +
-                    std::string(name) + "\"");
-
-        PyModule_AddObject(ptr(), name, obj.inc_ref().ptr() /* steals a reference */);
-    }
-};
-
-/// \ingroup python_builtins
-/// Return a dictionary representing the global variables in the current execution frame,
-/// or ``__main__.__dict__`` if there is no frame (usually when the interpreter is embedded).
-inline dict globals() {
-    PyObject *p = PyEval_GetGlobals();
-    return reinterpret_borrow<dict>(p ? p : module::import("__main__").attr("__dict__").ptr());
-}
-
-NAMESPACE_BEGIN(detail)
-/// Generic support for creating new Python heap types
-class generic_type : public object {
-    template <typename...> friend class class_;
-public:
-    PYBIND11_OBJECT_DEFAULT(generic_type, object, PyType_Check)
-protected:
-    void initialize(const type_record &rec) {
-        if (rec.scope && hasattr(rec.scope, rec.name))
-            pybind11_fail("generic_type: cannot initialize type \"" + std::string(rec.name) +
-                          "\": an object with that name is already defined");
-
-        if (rec.module_local ? get_local_type_info(*rec.type) : get_global_type_info(*rec.type))
-            pybind11_fail("generic_type: type \"" + std::string(rec.name) +
-                          "\" is already registered!");
-
-        m_ptr = make_new_python_type(rec);
-
-        /* Register supplemental type information in C++ dict */
-        auto *tinfo = new detail::type_info();
-        tinfo->type = (PyTypeObject *) m_ptr;
-        tinfo->cpptype = rec.type;
-        tinfo->type_size = rec.type_size;
-        tinfo->operator_new = rec.operator_new;
-        tinfo->holder_size_in_ptrs = size_in_ptrs(rec.holder_size);
-        tinfo->init_instance = rec.init_instance;
-        tinfo->dealloc = rec.dealloc;
-        tinfo->simple_type = true;
-        tinfo->simple_ancestors = true;
-        tinfo->default_holder = rec.default_holder;
-        tinfo->module_local = rec.module_local;
-
-        auto &internals = get_internals();
-        auto tindex = std::type_index(*rec.type);
-        tinfo->direct_conversions = &internals.direct_conversions[tindex];
-        if (rec.module_local)
-            registered_local_types_cpp()[tindex] = tinfo;
-        else
-            internals.registered_types_cpp[tindex] = tinfo;
-        internals.registered_types_py[(PyTypeObject *) m_ptr] = { tinfo };
-
-        if (rec.bases.size() > 1 || rec.multiple_inheritance) {
-            mark_parents_nonsimple(tinfo->type);
-            tinfo->simple_ancestors = false;
-        }
-        else if (rec.bases.size() == 1) {
-            auto parent_tinfo = get_type_info((PyTypeObject *) rec.bases[0].ptr());
-            tinfo->simple_ancestors = parent_tinfo->simple_ancestors;
-        }
-
-        if (rec.module_local) {
-            // Stash the local typeinfo and loader so that external modules can access it.
-            tinfo->module_local_load = &type_caster_generic::local_load;
-            setattr(m_ptr, PYBIND11_MODULE_LOCAL_ID, capsule(tinfo));
-        }
-    }
-
-    /// Helper function which tags all parents of a type using mult. inheritance
-    void mark_parents_nonsimple(PyTypeObject *value) {
-        auto t = reinterpret_borrow<tuple>(value->tp_bases);
-        for (handle h : t) {
-            auto tinfo2 = get_type_info((PyTypeObject *) h.ptr());
-            if (tinfo2)
-                tinfo2->simple_type = false;
-            mark_parents_nonsimple((PyTypeObject *) h.ptr());
-        }
-    }
-
-    void install_buffer_funcs(
-            buffer_info *(*get_buffer)(PyObject *, void *),
-            void *get_buffer_data) {
-        PyHeapTypeObject *type = (PyHeapTypeObject*) m_ptr;
-        auto tinfo = detail::get_type_info(&type->ht_type);
-
-        if (!type->ht_type.tp_as_buffer)
-            pybind11_fail(
-                "To be able to register buffer protocol support for the type '" +
-                std::string(tinfo->type->tp_name) +
-                "' the associated class<>(..) invocation must "
-                "include the pybind11::buffer_protocol() annotation!");
-
-        tinfo->get_buffer = get_buffer;
-        tinfo->get_buffer_data = get_buffer_data;
-    }
-
-    void def_property_static_impl(const char *name,
-                                  handle fget, handle fset,
-                                  detail::function_record *rec_fget) {
-        const auto is_static = !(rec_fget->is_method && rec_fget->scope);
-        const auto has_doc = rec_fget->doc && pybind11::options::show_user_defined_docstrings();
-
-        auto property = handle((PyObject *) (is_static ? get_internals().static_property_type
-                                                       : &PyProperty_Type));
-        attr(name) = property(fget.ptr() ? fget : none(),
-                              fset.ptr() ? fset : none(),
-                              /*deleter*/none(),
-                              pybind11::str(has_doc ? rec_fget->doc : ""));
-    }
-};
-
-/// Set the pointer to operator new if it exists. The cast is needed because it can be overloaded.
-template <typename T, typename = void_t<decltype(static_cast<void *(*)(size_t)>(T::operator new))>>
-void set_operator_new(type_record *r) { r->operator_new = &T::operator new; }
-
-template <typename> void set_operator_new(...) { }
-
-template <typename T, typename SFINAE = void> struct has_operator_delete : std::false_type { };
-template <typename T> struct has_operator_delete<T, void_t<decltype(static_cast<void (*)(void *)>(T::operator delete))>>
-    : std::true_type { };
-template <typename T, typename SFINAE = void> struct has_operator_delete_size : std::false_type { };
-template <typename T> struct has_operator_delete_size<T, void_t<decltype(static_cast<void (*)(void *, size_t)>(T::operator delete))>>
-    : std::true_type { };
-/// Call class-specific delete if it exists or global otherwise. Can also be an overload set.
-template <typename T, enable_if_t<has_operator_delete<T>::value, int> = 0>
-void call_operator_delete(T *p, size_t) { T::operator delete(p); }
-template <typename T, enable_if_t<!has_operator_delete<T>::value && has_operator_delete_size<T>::value, int> = 0>
-void call_operator_delete(T *p, size_t s) { T::operator delete(p, s); }
-
-inline void call_operator_delete(void *p, size_t) { ::operator delete(p); }
-
-NAMESPACE_END(detail)
-
-/// Given a pointer to a member function, cast it to its `Derived` version.
-/// Forward everything else unchanged.
-template <typename /*Derived*/, typename F>
-auto method_adaptor(F &&f) -> decltype(std::forward<F>(f)) { return std::forward<F>(f); }
-
-template <typename Derived, typename Return, typename Class, typename... Args>
-auto method_adaptor(Return (Class::*pmf)(Args...)) -> Return (Derived::*)(Args...) { return pmf; }
-
-template <typename Derived, typename Return, typename Class, typename... Args>
-auto method_adaptor(Return (Class::*pmf)(Args...) const) -> Return (Derived::*)(Args...) const { return pmf; }
-
-template <typename type_, typename... options>
-class class_ : public detail::generic_type {
-    template <typename T> using is_holder = detail::is_holder_type<type_, T>;
-    template <typename T> using is_subtype = detail::is_strict_base_of<type_, T>;
-    template <typename T> using is_base = detail::is_strict_base_of<T, type_>;
-    // struct instead of using here to help MSVC:
-    template <typename T> struct is_valid_class_option :
-        detail::any_of<is_holder<T>, is_subtype<T>, is_base<T>> {};
-
-public:
-    using type = type_;
-    using type_alias = detail::exactly_one_t<is_subtype, void, options...>;
-    constexpr static bool has_alias = !std::is_void<type_alias>::value;
-    using holder_type = detail::exactly_one_t<is_holder, std::unique_ptr<type>, options...>;
-
-    static_assert(detail::all_of<is_valid_class_option<options>...>::value,
-            "Unknown/invalid class_ template parameters provided");
-
-    static_assert(!has_alias || std::is_polymorphic<type>::value,
-            "Cannot use an alias class with a non-polymorphic type");
-
-    PYBIND11_OBJECT(class_, generic_type, PyType_Check)
-
-    template <typename... Extra>
-    class_(handle scope, const char *name, const Extra &... extra) {
-        using namespace detail;
-
-        // MI can only be specified via class_ template options, not constructor parameters
-        static_assert(
-            none_of<is_pyobject<Extra>...>::value || // no base class arguments, or:
-            (   constexpr_sum(is_pyobject<Extra>::value...) == 1 && // Exactly one base
-                constexpr_sum(is_base<options>::value...)   == 0 && // no template option bases
-                none_of<std::is_same<multiple_inheritance, Extra>...>::value), // no multiple_inheritance attr
-            "Error: multiple inheritance bases must be specified via class_ template options");
-
-        type_record record;
-        record.scope = scope;
-        record.name = name;
-        record.type = &typeid(type);
-        record.type_size = sizeof(conditional_t<has_alias, type_alias, type>);
-        record.holder_size = sizeof(holder_type);
-        record.init_instance = init_instance;
-        record.dealloc = dealloc;
-        record.default_holder = std::is_same<holder_type, std::unique_ptr<type>>::value;
-
-        set_operator_new<type>(&record);
-
-        /* Register base classes specified via template arguments to class_, if any */
-        PYBIND11_EXPAND_SIDE_EFFECTS(add_base<options>(record));
-
-        /* Process optional arguments, if any */
-        process_attributes<Extra...>::init(extra..., &record);
-
-        generic_type::initialize(record);
-
-        if (has_alias) {
-            auto &instances = record.module_local ? registered_local_types_cpp() : get_internals().registered_types_cpp;
-            instances[std::type_index(typeid(type_alias))] = instances[std::type_index(typeid(type))];
-        }
-    }
-
-    template <typename Base, detail::enable_if_t<is_base<Base>::value, int> = 0>
-    static void add_base(detail::type_record &rec) {
-        rec.add_base(typeid(Base), [](void *src) -> void * {
-            return static_cast<Base *>(reinterpret_cast<type *>(src));
-        });
-    }
-
-    template <typename Base, detail::enable_if_t<!is_base<Base>::value, int> = 0>
-    static void add_base(detail::type_record &) { }
-
-    template <typename Func, typename... Extra>
-    class_ &def(const char *name_, Func&& f, const Extra&... extra) {
-        cpp_function cf(method_adaptor<type>(std::forward<Func>(f)), name(name_), is_method(*this),
-                        sibling(getattr(*this, name_, none())), extra...);
-        attr(cf.name()) = cf;
-        return *this;
-    }
-
-    template <typename Func, typename... Extra> class_ &
-    def_static(const char *name_, Func &&f, const Extra&... extra) {
-        static_assert(!std::is_member_function_pointer<Func>::value,
-                "def_static(...) called with a non-static member function pointer");
-        cpp_function cf(std::forward<Func>(f), name(name_), scope(*this),
-                        sibling(getattr(*this, name_, none())), extra...);
-        attr(cf.name()) = cf;
-        return *this;
-    }
-
-    template <detail::op_id id, detail::op_type ot, typename L, typename R, typename... Extra>
-    class_ &def(const detail::op_<id, ot, L, R> &op, const Extra&... extra) {
-        op.execute(*this, extra...);
-        return *this;
-    }
-
-    template <detail::op_id id, detail::op_type ot, typename L, typename R, typename... Extra>
-    class_ & def_cast(const detail::op_<id, ot, L, R> &op, const Extra&... extra) {
-        op.execute_cast(*this, extra...);
-        return *this;
-    }
-
-    template <typename... Args, typename... Extra>
-    class_ &def(const detail::initimpl::constructor<Args...> &init, const Extra&... extra) {
-        init.execute(*this, extra...);
-        return *this;
-    }
-
-    template <typename... Args, typename... Extra>
-    class_ &def(const detail::initimpl::alias_constructor<Args...> &init, const Extra&... extra) {
-        init.execute(*this, extra...);
-        return *this;
-    }
-
-    template <typename... Args, typename... Extra>
-    class_ &def(detail::initimpl::factory<Args...> &&init, const Extra&... extra) {
-        std::move(init).execute(*this, extra...);
-        return *this;
-    }
-
-    template <typename... Args, typename... Extra>
-    class_ &def(detail::initimpl::pickle_factory<Args...> &&pf, const Extra &...extra) {
-        std::move(pf).execute(*this, extra...);
-        return *this;
-    }
-
-    template <typename Func> class_& def_buffer(Func &&func) {
-        struct capture { Func func; };
-        capture *ptr = new capture { std::forward<Func>(func) };
-        install_buffer_funcs([](PyObject *obj, void *ptr) -> buffer_info* {
-            detail::make_caster<type> caster;
-            if (!caster.load(obj, false))
-                return nullptr;
-            return new buffer_info(((capture *) ptr)->func(caster));
-        }, ptr);
-        return *this;
-    }
-
-    template <typename Return, typename Class, typename... Args>
-    class_ &def_buffer(Return (Class::*func)(Args...)) {
-        return def_buffer([func] (type &obj) { return (obj.*func)(); });
-    }
-
-    template <typename Return, typename Class, typename... Args>
-    class_ &def_buffer(Return (Class::*func)(Args...) const) {
-        return def_buffer([func] (const type &obj) { return (obj.*func)(); });
-    }
-
-    template <typename C, typename D, typename... Extra>
-    class_ &def_readwrite(const char *name, D C::*pm, const Extra&... extra) {
-        static_assert(std::is_base_of<C, type>::value, "def_readwrite() requires a class member (or base class member)");
-        cpp_function fget([pm](const type &c) -> const D &{ return c.*pm; }, is_method(*this)),
-                     fset([pm](type &c, const D &value) { c.*pm = value; }, is_method(*this));
-        def_property(name, fget, fset, return_value_policy::reference_internal, extra...);
-        return *this;
-    }
-
-    template <typename C, typename D, typename... Extra>
-    class_ &def_readonly(const char *name, const D C::*pm, const Extra& ...extra) {
-        static_assert(std::is_base_of<C, type>::value, "def_readonly() requires a class member (or base class member)");
-        cpp_function fget([pm](const type &c) -> const D &{ return c.*pm; }, is_method(*this));
-        def_property_readonly(name, fget, return_value_policy::reference_internal, extra...);
-        return *this;
-    }
-
-    template <typename D, typename... Extra>
-    class_ &def_readwrite_static(const char *name, D *pm, const Extra& ...extra) {
-        cpp_function fget([pm](object) -> const D &{ return *pm; }, scope(*this)),
-                     fset([pm](object, const D &value) { *pm = value; }, scope(*this));
-        def_property_static(name, fget, fset, return_value_policy::reference, extra...);
-        return *this;
-    }
-
-    template <typename D, typename... Extra>
-    class_ &def_readonly_static(const char *name, const D *pm, const Extra& ...extra) {
-        cpp_function fget([pm](object) -> const D &{ return *pm; }, scope(*this));
-        def_property_readonly_static(name, fget, return_value_policy::reference, extra...);
-        return *this;
-    }
-
-    /// Uses return_value_policy::reference_internal by default
-    template <typename Getter, typename... Extra>
-    class_ &def_property_readonly(const char *name, const Getter &fget, const Extra& ...extra) {
-        return def_property_readonly(name, cpp_function(method_adaptor<type>(fget)),
-                                     return_value_policy::reference_internal, extra...);
-    }
-
-    /// Uses cpp_function's return_value_policy by default
-    template <typename... Extra>
-    class_ &def_property_readonly(const char *name, const cpp_function &fget, const Extra& ...extra) {
-        return def_property(name, fget, cpp_function(), extra...);
-    }
-
-    /// Uses return_value_policy::reference by default
-    template <typename Getter, typename... Extra>
-    class_ &def_property_readonly_static(const char *name, const Getter &fget, const Extra& ...extra) {
-        return def_property_readonly_static(name, cpp_function(fget), return_value_policy::reference, extra...);
-    }
-
-    /// Uses cpp_function's return_value_policy by default
-    template <typename... Extra>
-    class_ &def_property_readonly_static(const char *name, const cpp_function &fget, const Extra& ...extra) {
-        return def_property_static(name, fget, cpp_function(), extra...);
-    }
-
-    /// Uses return_value_policy::reference_internal by default
-    template <typename Getter, typename Setter, typename... Extra>
-    class_ &def_property(const char *name, const Getter &fget, const Setter &fset, const Extra& ...extra) {
-        return def_property(name, fget, cpp_function(method_adaptor<type>(fset)), extra...);
-    }
-    template <typename Getter, typename... Extra>
-    class_ &def_property(const char *name, const Getter &fget, const cpp_function &fset, const Extra& ...extra) {
-        return def_property(name, cpp_function(method_adaptor<type>(fget)), fset,
-                            return_value_policy::reference_internal, extra...);
-    }
-
-    /// Uses cpp_function's return_value_policy by default
-    template <typename... Extra>
-    class_ &def_property(const char *name, const cpp_function &fget, const cpp_function &fset, const Extra& ...extra) {
-        return def_property_static(name, fget, fset, is_method(*this), extra...);
-    }
-
-    /// Uses return_value_policy::reference by default
-    template <typename Getter, typename... Extra>
-    class_ &def_property_static(const char *name, const Getter &fget, const cpp_function &fset, const Extra& ...extra) {
-        return def_property_static(name, cpp_function(fget), fset, return_value_policy::reference, extra...);
-    }
-
-    /// Uses cpp_function's return_value_policy by default
-    template <typename... Extra>
-    class_ &def_property_static(const char *name, const cpp_function &fget, const cpp_function &fset, const Extra& ...extra) {
-        auto rec_fget = get_function_record(fget), rec_fset = get_function_record(fset);
-        char *doc_prev = rec_fget->doc; /* 'extra' field may include a property-specific documentation string */
-        detail::process_attributes<Extra...>::init(extra..., rec_fget);
-        if (rec_fget->doc && rec_fget->doc != doc_prev) {
-            free(doc_prev);
-            rec_fget->doc = strdup(rec_fget->doc);
-        }
-        if (rec_fset) {
-            doc_prev = rec_fset->doc;
-            detail::process_attributes<Extra...>::init(extra..., rec_fset);
-            if (rec_fset->doc && rec_fset->doc != doc_prev) {
-                free(doc_prev);
-                rec_fset->doc = strdup(rec_fset->doc);
-            }
-        }
-        def_property_static_impl(name, fget, fset, rec_fget);
-        return *this;
-    }
-
-private:
-    /// Initialize holder object, variant 1: object derives from enable_shared_from_this
-    template <typename T>
-    static void init_holder(detail::instance *inst, detail::value_and_holder &v_h,
-            const holder_type * /* unused */, const std::enable_shared_from_this<T> * /* dummy */) {
-        try {
-            auto sh = std::dynamic_pointer_cast<typename holder_type::element_type>(
-                    v_h.value_ptr<type>()->shared_from_this());
-            if (sh) {
-                new (&v_h.holder<holder_type>()) holder_type(std::move(sh));
-                v_h.set_holder_constructed();
-            }
-        } catch (const std::bad_weak_ptr &) {}
-
-        if (!v_h.holder_constructed() && inst->owned) {
-            new (&v_h.holder<holder_type>()) holder_type(v_h.value_ptr<type>());
-            v_h.set_holder_constructed();
-        }
-    }
-
-    static void init_holder_from_existing(const detail::value_and_holder &v_h,
-            const holder_type *holder_ptr, std::true_type /*is_copy_constructible*/) {
-        new (&v_h.holder<holder_type>()) holder_type(*reinterpret_cast<const holder_type *>(holder_ptr));
-    }
-
-    static void init_holder_from_existing(const detail::value_and_holder &v_h,
-            const holder_type *holder_ptr, std::false_type /*is_copy_constructible*/) {
-        new (&v_h.holder<holder_type>()) holder_type(std::move(*const_cast<holder_type *>(holder_ptr)));
-    }
-
-    /// Initialize holder object, variant 2: try to construct from existing holder object, if possible
-    static void init_holder(detail::instance *inst, detail::value_and_holder &v_h,
-            const holder_type *holder_ptr, const void * /* dummy -- not enable_shared_from_this<T>) */) {
-        if (holder_ptr) {
-            init_holder_from_existing(v_h, holder_ptr, std::is_copy_constructible<holder_type>());
-            v_h.set_holder_constructed();
-        } else if (inst->owned || detail::always_construct_holder<holder_type>::value) {
-            new (&v_h.holder<holder_type>()) holder_type(v_h.value_ptr<type>());
-            v_h.set_holder_constructed();
-        }
-    }
-
-    /// Performs instance initialization including constructing a holder and registering the known
-    /// instance.  Should be called as soon as the `type` value_ptr is set for an instance.  Takes an
-    /// optional pointer to an existing holder to use; if not specified and the instance is
-    /// `.owned`, a new holder will be constructed to manage the value pointer.
-    static void init_instance(detail::instance *inst, const void *holder_ptr) {
-        auto v_h = inst->get_value_and_holder(detail::get_type_info(typeid(type)));
-        if (!v_h.instance_registered()) {
-            register_instance(inst, v_h.value_ptr(), v_h.type);
-            v_h.set_instance_registered();
-        }
-        init_holder(inst, v_h, (const holder_type *) holder_ptr, v_h.value_ptr<type>());
-    }
-
-    /// Deallocates an instance; via holder, if constructed; otherwise via operator delete.
-    static void dealloc(detail::value_and_holder &v_h) {
-        if (v_h.holder_constructed()) {
-            v_h.holder<holder_type>().~holder_type();
-            v_h.set_holder_constructed(false);
-        }
-        else {
-            detail::call_operator_delete(v_h.value_ptr<type>(), v_h.type->type_size);
-        }
-        v_h.value_ptr() = nullptr;
-    }
-
-    static detail::function_record *get_function_record(handle h) {
-        h = detail::get_function(h);
-        return h ? (detail::function_record *) reinterpret_borrow<capsule>(PyCFunction_GET_SELF(h.ptr()))
-                 : nullptr;
-    }
-};
-
-/// Binds an existing constructor taking arguments Args...
-template <typename... Args> detail::initimpl::constructor<Args...> init() { return {}; }
-/// Like `init<Args...>()`, but the instance is always constructed through the alias class (even
-/// when not inheriting on the Python side).
-template <typename... Args> detail::initimpl::alias_constructor<Args...> init_alias() { return {}; }
-
-/// Binds a factory function as a constructor
-template <typename Func, typename Ret = detail::initimpl::factory<Func>>
-Ret init(Func &&f) { return {std::forward<Func>(f)}; }
-
-/// Dual-argument factory function: the first function is called when no alias is needed, the second
-/// when an alias is needed (i.e. due to python-side inheritance).  Arguments must be identical.
-template <typename CFunc, typename AFunc, typename Ret = detail::initimpl::factory<CFunc, AFunc>>
-Ret init(CFunc &&c, AFunc &&a) {
-    return {std::forward<CFunc>(c), std::forward<AFunc>(a)};
-}
-
-/// Binds pickling functions `__getstate__` and `__setstate__` and ensures that the type
-/// returned by `__getstate__` is the same as the argument accepted by `__setstate__`.
-template <typename GetState, typename SetState>
-detail::initimpl::pickle_factory<GetState, SetState> pickle(GetState &&g, SetState &&s) {
-    return {std::forward<GetState>(g), std::forward<SetState>(s)};
-}
-
-/// Binds C++ enumerations and enumeration classes to Python
-template <typename Type> class enum_ : public class_<Type> {
-public:
-    using class_<Type>::def;
-    using class_<Type>::def_property_readonly_static;
-    using Scalar = typename std::underlying_type<Type>::type;
-
-    template <typename... Extra>
-    enum_(const handle &scope, const char *name, const Extra&... extra)
-      : class_<Type>(scope, name, extra...), m_entries(), m_parent(scope) {
-
-        constexpr bool is_arithmetic = detail::any_of<std::is_same<arithmetic, Extra>...>::value;
-
-        auto m_entries_ptr = m_entries.inc_ref().ptr();
-        def("__repr__", [name, m_entries_ptr](Type value) -> pybind11::str {
-            for (const auto &kv : reinterpret_borrow<dict>(m_entries_ptr)) {
-                if (pybind11::cast<Type>(kv.second) == value)
-                    return pybind11::str("{}.{}").format(name, kv.first);
-            }
-            return pybind11::str("{}.???").format(name);
-        });
-        def_property_readonly_static("__members__", [m_entries_ptr](object /* self */) {
-            dict m;
-            for (const auto &kv : reinterpret_borrow<dict>(m_entries_ptr))
-                m[kv.first] = kv.second;
-            return m;
-        }, return_value_policy::copy);
-        def(init([](Scalar i) { return static_cast<Type>(i); }));
-        def("__int__", [](Type value) { return (Scalar) value; });
-        #if PY_MAJOR_VERSION < 3
-            def("__long__", [](Type value) { return (Scalar) value; });
-        #endif
-        def("__eq__", [](const Type &value, Type *value2) { return value2 && value == *value2; });
-        def("__ne__", [](const Type &value, Type *value2) { return !value2 || value != *value2; });
-        if (is_arithmetic) {
-            def("__lt__", [](const Type &value, Type *value2) { return value2 && value < *value2; });
-            def("__gt__", [](const Type &value, Type *value2) { return value2 && value > *value2; });
-            def("__le__", [](const Type &value, Type *value2) { return value2 && value <= *value2; });
-            def("__ge__", [](const Type &value, Type *value2) { return value2 && value >= *value2; });
-        }
-        if (std::is_convertible<Type, Scalar>::value) {
-            // Don't provide comparison with the underlying type if the enum isn't convertible,
-            // i.e. if Type is a scoped enum, mirroring the C++ behaviour.  (NB: we explicitly
-            // convert Type to Scalar below anyway because this needs to compile).
-            def("__eq__", [](const Type &value, Scalar value2) { return (Scalar) value == value2; });
-            def("__ne__", [](const Type &value, Scalar value2) { return (Scalar) value != value2; });
-            if (is_arithmetic) {
-                def("__lt__", [](const Type &value, Scalar value2) { return (Scalar) value < value2; });
-                def("__gt__", [](const Type &value, Scalar value2) { return (Scalar) value > value2; });
-                def("__le__", [](const Type &value, Scalar value2) { return (Scalar) value <= value2; });
-                def("__ge__", [](const Type &value, Scalar value2) { return (Scalar) value >= value2; });
-                def("__invert__", [](const Type &value) { return ~((Scalar) value); });
-                def("__and__", [](const Type &value, Scalar value2) { return (Scalar) value & value2; });
-                def("__or__", [](const Type &value, Scalar value2) { return (Scalar) value | value2; });
-                def("__xor__", [](const Type &value, Scalar value2) { return (Scalar) value ^ value2; });
-                def("__rand__", [](const Type &value, Scalar value2) { return (Scalar) value & value2; });
-                def("__ror__", [](const Type &value, Scalar value2) { return (Scalar) value | value2; });
-                def("__rxor__", [](const Type &value, Scalar value2) { return (Scalar) value ^ value2; });
-                def("__and__", [](const Type &value, const Type &value2) { return (Scalar) value & (Scalar) value2; });
-                def("__or__", [](const Type &value, const Type &value2) { return (Scalar) value | (Scalar) value2; });
-                def("__xor__", [](const Type &value, const Type &value2) { return (Scalar) value ^ (Scalar) value2; });
-            }
-        }
-        def("__hash__", [](const Type &value) { return (Scalar) value; });
-        // Pickling and unpickling -- needed for use with the 'multiprocessing' module
-        def(pickle([](const Type &value) { return pybind11::make_tuple((Scalar) value); },
-                   [](tuple t) { return static_cast<Type>(t[0].cast<Scalar>()); }));
-    }
-
-    /// Export enumeration entries into the parent scope
-    enum_& export_values() {
-        for (const auto &kv : m_entries)
-            m_parent.attr(kv.first) = kv.second;
-        return *this;
-    }
-
-    /// Add an enumeration entry
-    enum_& value(char const* name, Type value) {
-        auto v = pybind11::cast(value, return_value_policy::copy);
-        this->attr(name) = v;
-        m_entries[pybind11::str(name)] = v;
-        return *this;
-    }
-
-private:
-    dict m_entries;
-    handle m_parent;
-};
-
-NAMESPACE_BEGIN(detail)
-
-
-inline void keep_alive_impl(handle nurse, handle patient) {
-    if (!nurse || !patient)
-        pybind11_fail("Could not activate keep_alive!");
-
-    if (patient.is_none() || nurse.is_none())
-        return; /* Nothing to keep alive or nothing to be kept alive by */
-
-    auto tinfo = all_type_info(Py_TYPE(nurse.ptr()));
-    if (!tinfo.empty()) {
-        /* It's a pybind-registered type, so we can store the patient in the
-         * internal list. */
-        add_patient(nurse.ptr(), patient.ptr());
-    }
-    else {
-        /* Fall back to clever approach based on weak references taken from
-         * Boost.Python. This is not used for pybind-registered types because
-         * the objects can be destroyed out-of-order in a GC pass. */
-        cpp_function disable_lifesupport(
-            [patient](handle weakref) { patient.dec_ref(); weakref.dec_ref(); });
-
-        weakref wr(nurse, disable_lifesupport);
-
-        patient.inc_ref(); /* reference patient and leak the weak reference */
-        (void) wr.release();
-    }
-}
-
-PYBIND11_NOINLINE inline void keep_alive_impl(size_t Nurse, size_t Patient, function_call &call, handle ret) {
-    auto get_arg = [&](size_t n) {
-        if (n == 0)
-            return ret;
-        else if (n == 1 && call.init_self)
-            return call.init_self;
-        else if (n <= call.args.size())
-            return call.args[n - 1];
-        return handle();
-    };
-
-    keep_alive_impl(get_arg(Nurse), get_arg(Patient));
-}
-
-inline std::pair<decltype(internals::registered_types_py)::iterator, bool> all_type_info_get_cache(PyTypeObject *type) {
-    auto res = get_internals().registered_types_py
-#ifdef __cpp_lib_unordered_map_try_emplace
-        .try_emplace(type);
-#else
-        .emplace(type, std::vector<detail::type_info *>());
-#endif
-    if (res.second) {
-        // New cache entry created; set up a weak reference to automatically remove it if the type
-        // gets destroyed:
-        weakref((PyObject *) type, cpp_function([type](handle wr) {
-            get_internals().registered_types_py.erase(type);
-            wr.dec_ref();
-        })).release();
-    }
-
-    return res;
-}
-
-template <typename Iterator, typename Sentinel, bool KeyIterator, return_value_policy Policy>
-struct iterator_state {
-    Iterator it;
-    Sentinel end;
-    bool first_or_done;
-};
-
-NAMESPACE_END(detail)
-
-/// Makes a python iterator from a first and past-the-end C++ InputIterator.
-template <return_value_policy Policy = return_value_policy::reference_internal,
-          typename Iterator,
-          typename Sentinel,
-          typename ValueType = decltype(*std::declval<Iterator>()),
-          typename... Extra>
-iterator make_iterator(Iterator first, Sentinel last, Extra &&... extra) {
-    typedef detail::iterator_state<Iterator, Sentinel, false, Policy> state;
-
-    if (!detail::get_type_info(typeid(state), false)) {
-        class_<state>(handle(), "iterator", pybind11::module_local())
-            .def("__iter__", [](state &s) -> state& { return s; })
-            .def("__next__", [](state &s) -> ValueType {
-                if (!s.first_or_done)
-                    ++s.it;
-                else
-                    s.first_or_done = false;
-                if (s.it == s.end) {
-                    s.first_or_done = true;
-                    throw stop_iteration();
-                }
-                return *s.it;
-            }, std::forward<Extra>(extra)..., Policy);
-    }
-
-    return cast(state{first, last, true});
-}
-
-/// Makes an python iterator over the keys (`.first`) of a iterator over pairs from a
-/// first and past-the-end InputIterator.
-template <return_value_policy Policy = return_value_policy::reference_internal,
-          typename Iterator,
-          typename Sentinel,
-          typename KeyType = decltype((*std::declval<Iterator>()).first),
-          typename... Extra>
-iterator make_key_iterator(Iterator first, Sentinel last, Extra &&... extra) {
-    typedef detail::iterator_state<Iterator, Sentinel, true, Policy> state;
-
-    if (!detail::get_type_info(typeid(state), false)) {
-        class_<state>(handle(), "iterator", pybind11::module_local())
-            .def("__iter__", [](state &s) -> state& { return s; })
-            .def("__next__", [](state &s) -> KeyType {
-                if (!s.first_or_done)
-                    ++s.it;
-                else
-                    s.first_or_done = false;
-                if (s.it == s.end) {
-                    s.first_or_done = true;
-                    throw stop_iteration();
-                }
-                return (*s.it).first;
-            }, std::forward<Extra>(extra)..., Policy);
-    }
-
-    return cast(state{first, last, true});
-}
-
-/// Makes an iterator over values of an stl container or other container supporting
-/// `std::begin()`/`std::end()`
-template <return_value_policy Policy = return_value_policy::reference_internal,
-          typename Type, typename... Extra> iterator make_iterator(Type &value, Extra&&... extra) {
-    return make_iterator<Policy>(std::begin(value), std::end(value), extra...);
-}
-
-/// Makes an iterator over the keys (`.first`) of a stl map-like container supporting
-/// `std::begin()`/`std::end()`
-template <return_value_policy Policy = return_value_policy::reference_internal,
-          typename Type, typename... Extra> iterator make_key_iterator(Type &value, Extra&&... extra) {
-    return make_key_iterator<Policy>(std::begin(value), std::end(value), extra...);
-}
-
-template <typename InputType, typename OutputType> void implicitly_convertible() {
-    struct set_flag {
-        bool &flag;
-        set_flag(bool &flag) : flag(flag) { flag = true; }
-        ~set_flag() { flag = false; }
-    };
-    auto implicit_caster = [](PyObject *obj, PyTypeObject *type) -> PyObject * {
-        static bool currently_used = false;
-        if (currently_used) // implicit conversions are non-reentrant
-            return nullptr;
-        set_flag flag_helper(currently_used);
-        if (!detail::make_caster<InputType>().load(obj, false))
-            return nullptr;
-        tuple args(1);
-        args[0] = obj;
-        PyObject *result = PyObject_Call((PyObject *) type, args.ptr(), nullptr);
-        if (result == nullptr)
-            PyErr_Clear();
-        return result;
-    };
-
-    if (auto tinfo = detail::get_type_info(typeid(OutputType)))
-        tinfo->implicit_conversions.push_back(implicit_caster);
-    else
-        pybind11_fail("implicitly_convertible: Unable to find type " + type_id<OutputType>());
-}
-
-template <typename ExceptionTranslator>
-void register_exception_translator(ExceptionTranslator&& translator) {
-    detail::get_internals().registered_exception_translators.push_front(
-        std::forward<ExceptionTranslator>(translator));
-}
-
-/**
- * Wrapper to generate a new Python exception type.
- *
- * This should only be used with PyErr_SetString for now.
- * It is not (yet) possible to use as a py::base.
- * Template type argument is reserved for future use.
- */
-template <typename type>
-class exception : public object {
-public:
-    exception(handle scope, const char *name, PyObject *base = PyExc_Exception) {
-        std::string full_name = scope.attr("__name__").cast<std::string>() +
-                                std::string(".") + name;
-        m_ptr = PyErr_NewException(const_cast<char *>(full_name.c_str()), base, NULL);
-        if (hasattr(scope, name))
-            pybind11_fail("Error during initialization: multiple incompatible "
-                          "definitions with name \"" + std::string(name) + "\"");
-        scope.attr(name) = *this;
-    }
-
-    // Sets the current python exception to this exception object with the given message
-    void operator()(const char *message) {
-        PyErr_SetString(m_ptr, message);
-    }
-};
-
-/**
- * Registers a Python exception in `m` of the given `name` and installs an exception translator to
- * translate the C++ exception to the created Python exception using the exceptions what() method.
- * This is intended for simple exception translations; for more complex translation, register the
- * exception object and translator directly.
- */
-template <typename CppException>
-exception<CppException> &register_exception(handle scope,
-                                            const char *name,
-                                            PyObject *base = PyExc_Exception) {
-    static exception<CppException> ex(scope, name, base);
-    register_exception_translator([](std::exception_ptr p) {
-        if (!p) return;
-        try {
-            std::rethrow_exception(p);
-        } catch (const CppException &e) {
-            ex(e.what());
-        }
-    });
-    return ex;
-}
-
-NAMESPACE_BEGIN(detail)
-PYBIND11_NOINLINE inline void print(tuple args, dict kwargs) {
-    auto strings = tuple(args.size());
-    for (size_t i = 0; i < args.size(); ++i) {
-        strings[i] = str(args[i]);
-    }
-    auto sep = kwargs.contains("sep") ? kwargs["sep"] : cast(" ");
-    auto line = sep.attr("join")(strings);
-
-    object file;
-    if (kwargs.contains("file")) {
-        file = kwargs["file"].cast<object>();
-    } else {
-        try {
-            file = module::import("sys").attr("stdout");
-        } catch (const error_already_set &) {
-            /* If print() is called from code that is executed as
-               part of garbage collection during interpreter shutdown,
-               importing 'sys' can fail. Give up rather than crashing the
-               interpreter in this case. */
-            return;
-        }
-    }
-
-    auto write = file.attr("write");
-    write(line);
-    write(kwargs.contains("end") ? kwargs["end"] : cast("\n"));
-
-    if (kwargs.contains("flush") && kwargs["flush"].cast<bool>())
-        file.attr("flush")();
-}
-NAMESPACE_END(detail)
-
-template <return_value_policy policy = return_value_policy::automatic_reference, typename... Args>
-void print(Args &&...args) {
-    auto c = detail::collect_arguments<policy>(std::forward<Args>(args)...);
-    detail::print(c.args(), c.kwargs());
-}
-
-#if defined(WITH_THREAD)
-class gil_scoped_acquire {
-    PyGILState_STATE state;
-public:
-    gil_scoped_acquire() { state = PyGILState_Ensure(); }
-    ~gil_scoped_acquire() { PyGILState_Release(state); }
-};
-
-class gil_scoped_release {
-    PyThreadState *state;
-public:
-    gil_scoped_release() { state = PyEval_SaveThread(); }
-    ~gil_scoped_release() { PyEval_RestoreThread(state); }
-};
-#else
-class gil_scoped_acquire { };
-class gil_scoped_release { };
-#endif
-
-error_already_set::~error_already_set() {
-    if (type) {
-        gil_scoped_acquire gil;
-        type.release().dec_ref();
-        value.release().dec_ref();
-        trace.release().dec_ref();
-    }
-}
-
-inline function get_type_overload(const void *this_ptr, const detail::type_info *this_type, const char *name)  {
-    handle self = detail::get_object_handle(this_ptr, this_type);
-    if (!self)
-        return function();
-    handle type = self.get_type();
-    auto key = std::make_pair(type.ptr(), name);
-
-    /* Cache functions that aren't overloaded in Python to avoid
-       many costly Python dictionary lookups below */
-    auto &cache = detail::get_internals().inactive_overload_cache;
-    if (cache.find(key) != cache.end())
-        return function();
-
-    function overload = getattr(self, name, function());
-    if (overload.is_cpp_function()) {
-        cache.insert(key);
-        return function();
-    }
-
-    /* Don't call dispatch code if invoked from overridden function.
-       Unfortunately this doesn't work on PyPy. */
-#if !defined(PYPY_VERSION)
-    PyFrameObject *frame = PyThreadState_Get()->frame;
-    if (frame && (std::string) str(frame->f_code->co_name) == name &&
-        frame->f_code->co_argcount > 0) {
-        PyFrame_FastToLocals(frame);
-        PyObject *self_caller = PyDict_GetItem(
-            frame->f_locals, PyTuple_GET_ITEM(frame->f_code->co_varnames, 0));
-        if (self_caller == self.ptr())
-            return function();
-    }
-#else
-    /* PyPy currently doesn't provide a detailed cpyext emulation of
-       frame objects, so we have to emulate this using Python. This
-       is going to be slow..*/
-    dict d; d["self"] = self; d["name"] = pybind11::str(name);
-    PyObject *result = PyRun_String(
-        "import inspect\n"
-        "frame = inspect.currentframe()\n"
-        "if frame is not None:\n"
-        "    frame = frame.f_back\n"
-        "    if frame is not None and str(frame.f_code.co_name) == name and "
-        "frame.f_code.co_argcount > 0:\n"
-        "        self_caller = frame.f_locals[frame.f_code.co_varnames[0]]\n"
-        "        if self_caller == self:\n"
-        "            self = None\n",
-        Py_file_input, d.ptr(), d.ptr());
-    if (result == nullptr)
-        throw error_already_set();
-    if (d["self"].is_none())
-        return function();
-    Py_DECREF(result);
-#endif
-
-    return overload;
-}
-
-template <class T> function get_overload(const T *this_ptr, const char *name) {
-    auto tinfo = detail::get_type_info(typeid(T));
-    return tinfo ? get_type_overload(this_ptr, tinfo, name) : function();
-}
-
-#define PYBIND11_OVERLOAD_INT(ret_type, cname, name, ...) { \
-        pybind11::gil_scoped_acquire gil; \
-        pybind11::function overload = pybind11::get_overload(static_cast<const cname *>(this), name); \
-        if (overload) { \
-            auto o = overload(__VA_ARGS__); \
-            if (pybind11::detail::cast_is_temporary_value_reference<ret_type>::value) { \
-                static pybind11::detail::overload_caster_t<ret_type> caster; \
-                return pybind11::detail::cast_ref<ret_type>(std::move(o), caster); \
-            } \
-            else return pybind11::detail::cast_safe<ret_type>(std::move(o)); \
-        } \
-    }
-
-#define PYBIND11_OVERLOAD_NAME(ret_type, cname, name, fn, ...) \
-    PYBIND11_OVERLOAD_INT(ret_type, cname, name, __VA_ARGS__) \
-    return cname::fn(__VA_ARGS__)
-
-#define PYBIND11_OVERLOAD_PURE_NAME(ret_type, cname, name, fn, ...) \
-    PYBIND11_OVERLOAD_INT(ret_type, cname, name, __VA_ARGS__) \
-    pybind11::pybind11_fail("Tried to call pure virtual function \"" #cname "::" name "\"");
-
-#define PYBIND11_OVERLOAD(ret_type, cname, fn, ...) \
-    PYBIND11_OVERLOAD_NAME(ret_type, cname, #fn, fn, __VA_ARGS__)
-
-#define PYBIND11_OVERLOAD_PURE(ret_type, cname, fn, ...) \
-    PYBIND11_OVERLOAD_PURE_NAME(ret_type, cname, #fn, fn, __VA_ARGS__)
-
-NAMESPACE_END(PYBIND11_NAMESPACE)
-
-#if defined(_MSC_VER)
-#  pragma warning(pop)
-#elif defined(__INTEL_COMPILER)
-/* Leave ignored warnings on */
-#elif defined(__GNUG__) && !defined(__clang__)
-#  pragma GCC diagnostic pop
-#endif
diff --git a/Patches/pybind11/pybind11.h b/Patches/pybind11/pybind11.h
new file mode 100644
index 00000000..4551d548
--- /dev/null
+++ b/Patches/pybind11/pybind11.h
@@ -0,0 +1,2883 @@
+/*
+    pybind11/pybind11.h: Main header file of the C++11 python
+    binding generator library
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    All rights reserved. Use of this source code is governed by a
+    BSD-style license that can be found in the LICENSE file.
+*/
+
+#pragma once
+
+#include "detail/class.h"
+#include "detail/init.h"
+#include "attr.h"
+#include "gil.h"
+#include "options.h"
+
+#include <cstdlib>
+#include <cstring>
+#include <memory>
+#include <new>
+#include <string>
+#include <utility>
+#include <vector>
+
+#if defined(__cpp_lib_launder) && !(defined(_MSC_VER) && (_MSC_VER < 1914))
+#    define PYBIND11_STD_LAUNDER std::launder
+#    define PYBIND11_HAS_STD_LAUNDER 1
+#else
+#    define PYBIND11_STD_LAUNDER
+#    define PYBIND11_HAS_STD_LAUNDER 0
+#endif
+#if defined(__GNUG__) && !defined(__clang__)
+#    include <cxxabi.h>
+#endif
+
+PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+
+/* https://stackoverflow.com/questions/46798456/handling-gccs-noexcept-type-warning
+   This warning is about ABI compatibility, not code health.
+   It is only actually needed in a couple places, but apparently GCC 7 "generates this warning if
+   and only if the first template instantiation ... involves noexcept" [stackoverflow], therefore
+   it could get triggered from seemingly random places, depending on user code.
+   No other GCC version generates this warning.
+ */
+#if defined(__GNUC__) && __GNUC__ == 7
+PYBIND11_WARNING_DISABLE_GCC("-Wnoexcept-type")
+#endif
+
+PYBIND11_WARNING_DISABLE_MSVC(4127)
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+// Apply all the extensions translators from a list
+// Return true if one of the translators completed without raising an exception
+// itself. Return of false indicates that if there are other translators
+// available, they should be tried.
+inline bool apply_exception_translators(std::forward_list<ExceptionTranslator> &translators) {
+    auto last_exception = std::current_exception();
+
+    for (auto &translator : translators) {
+        try {
+            translator(last_exception);
+            return true;
+        } catch (...) {
+            last_exception = std::current_exception();
+        }
+    }
+    return false;
+}
+
+#if defined(_MSC_VER)
+#    define PYBIND11_COMPAT_STRDUP _strdup
+#else
+#    define PYBIND11_COMPAT_STRDUP strdup
+#endif
+
+PYBIND11_NAMESPACE_END(detail)
+
+/// Wraps an arbitrary C++ function/method/lambda function/.. into a callable Python object
+class cpp_function : public function {
+public:
+    cpp_function() = default;
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(std::nullptr_t) {}
+
+    /// Construct a cpp_function from a vanilla function pointer
+    template <typename Return, typename... Args, typename... Extra>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(Return (*f)(Args...), const Extra &...extra) {
+        initialize(f, f, extra...);
+    }
+
+    /// Construct a cpp_function from a lambda function (possibly with internal state)
+    template <typename Func,
+              typename... Extra,
+              typename = detail::enable_if_t<detail::is_lambda<Func>::value>>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(Func &&f, const Extra &...extra) {
+        initialize(
+            std::forward<Func>(f), (detail::function_signature_t<Func> *) nullptr, extra...);
+    }
+
+    /// Construct a cpp_function from a class method (non-const, no ref-qualifier)
+    template <typename Return, typename Class, typename... Arg, typename... Extra>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(Return (Class::*f)(Arg...), const Extra &...extra) {
+        initialize(
+            [f](Class *c, Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
+            (Return(*)(Class *, Arg...)) nullptr,
+            extra...);
+    }
+
+    /// Construct a cpp_function from a class method (non-const, lvalue ref-qualifier)
+    /// A copy of the overload for non-const functions without explicit ref-qualifier
+    /// but with an added `&`.
+    template <typename Return, typename Class, typename... Arg, typename... Extra>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(Return (Class::*f)(Arg...) &, const Extra &...extra) {
+        initialize(
+            [f](Class *c, Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
+            (Return(*)(Class *, Arg...)) nullptr,
+            extra...);
+    }
+
+    /// Construct a cpp_function from a class method (const, no ref-qualifier)
+    template <typename Return, typename Class, typename... Arg, typename... Extra>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(Return (Class::*f)(Arg...) const, const Extra &...extra) {
+        initialize([f](const Class *c,
+                       Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
+                   (Return(*)(const Class *, Arg...)) nullptr,
+                   extra...);
+    }
+
+    /// Construct a cpp_function from a class method (const, lvalue ref-qualifier)
+    /// A copy of the overload for const functions without explicit ref-qualifier
+    /// but with an added `&`.
+    template <typename Return, typename Class, typename... Arg, typename... Extra>
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    cpp_function(Return (Class::*f)(Arg...) const &, const Extra &...extra) {
+        initialize([f](const Class *c,
+                       Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
+                   (Return(*)(const Class *, Arg...)) nullptr,
+                   extra...);
+    }
+
+    /// Return the function name
+    object name() const { return attr("__name__"); }
+
+protected:
+    struct InitializingFunctionRecordDeleter {
+        // `destruct(function_record, false)`: `initialize_generic` copies strings and
+        // takes care of cleaning up in case of exceptions. So pass `false` to `free_strings`.
+        void operator()(detail::function_record *rec) { destruct(rec, false); }
+    };
+    using unique_function_record
+        = std::unique_ptr<detail::function_record, InitializingFunctionRecordDeleter>;
+
+    /// Space optimization: don't inline this frequently instantiated fragment
+    PYBIND11_NOINLINE unique_function_record make_function_record() {
+        return unique_function_record(new detail::function_record());
+    }
+
+    /// Special internal constructor for functors, lambda functions, etc.
+    template <typename Func, typename Return, typename... Args, typename... Extra>
+    void initialize(Func &&f, Return (*)(Args...), const Extra &...extra) {
+        using namespace detail;
+        struct capture {
+            remove_reference_t<Func> f;
+        };
+
+        /* Store the function including any extra state it might have (e.g. a lambda capture
+         * object) */
+        // The unique_ptr makes sure nothing is leaked in case of an exception.
+        auto unique_rec = make_function_record();
+        auto *rec = unique_rec.get();
+
+        /* Store the capture object directly in the function record if there is enough space */
+        if (sizeof(capture) <= sizeof(rec->data)) {
+            /* Without these pragmas, GCC warns that there might not be
+               enough space to use the placement new operator. However, the
+               'if' statement above ensures that this is the case. */
+            PYBIND11_WARNING_PUSH
+
+#if defined(__GNUG__) && __GNUC__ >= 6
+            PYBIND11_WARNING_DISABLE_GCC("-Wplacement-new")
+#endif
+
+            new ((capture *) &rec->data) capture{std::forward<Func>(f)};
+
+#if !PYBIND11_HAS_STD_LAUNDER
+            PYBIND11_WARNING_DISABLE_GCC("-Wstrict-aliasing")
+#endif
+
+            // UB without std::launder, but without breaking ABI and/or
+            // a significant refactoring it's "impossible" to solve.
+            if (!std::is_trivially_destructible<capture>::value) {
+                rec->free_data = [](function_record *r) {
+                    auto data = PYBIND11_STD_LAUNDER((capture *) &r->data);
+                    (void) data;
+                    data->~capture();
+                };
+            }
+            PYBIND11_WARNING_POP
+        } else {
+            rec->data[0] = new capture{std::forward<Func>(f)};
+            rec->free_data = [](function_record *r) { delete ((capture *) r->data[0]); };
+        }
+
+        /* Type casters for the function arguments and return value */
+        using cast_in = argument_loader<Args...>;
+        using cast_out
+            = make_caster<conditional_t<std::is_void<Return>::value, void_type, Return>>;
+
+        static_assert(
+            expected_num_args<Extra...>(
+                sizeof...(Args), cast_in::args_pos >= 0, cast_in::has_kwargs),
+            "The number of argument annotations does not match the number of function arguments");
+
+        /* Dispatch code which converts function arguments and performs the actual function call */
+        rec->impl = [](function_call &call) -> handle {
+            cast_in args_converter;
+
+            /* Try to cast the function arguments into the C++ domain */
+            if (!args_converter.load_args(call)) {
+                return PYBIND11_TRY_NEXT_OVERLOAD;
+            }
+
+            /* Invoke call policy pre-call hook */
+            process_attributes<Extra...>::precall(call);
+
+            /* Get a pointer to the capture object */
+            const auto *data = (sizeof(capture) <= sizeof(call.func.data) ? &call.func.data
+                                                                          : call.func.data[0]);
+            auto *cap = const_cast<capture *>(reinterpret_cast<const capture *>(data));
+
+            /* Override policy for rvalues -- usually to enforce rvp::move on an rvalue */
+            return_value_policy policy
+                = return_value_policy_override<Return>::policy(call.func.policy);
+
+            /* Function scope guard -- defaults to the compile-to-nothing `void_type` */
+            using Guard = extract_guard_t<Extra...>;
+
+            /* Perform the function call */
+            handle result
+                = cast_out::cast(std::move(args_converter).template call<Return, Guard>(cap->f),
+                                 policy,
+                                 call.parent);
+
+            /* Invoke call policy post-call hook */
+            process_attributes<Extra...>::postcall(call, result);
+
+            return result;
+        };
+
+        rec->nargs_pos = cast_in::args_pos >= 0
+                             ? static_cast<std::uint16_t>(cast_in::args_pos)
+                             : sizeof...(Args) - cast_in::has_kwargs; // Will get reduced more if
+                                                                      // we have a kw_only
+        rec->has_args = cast_in::args_pos >= 0;
+        rec->has_kwargs = cast_in::has_kwargs;
+
+        /* Process any user-provided function attributes */
+        process_attributes<Extra...>::init(extra..., rec);
+
+        {
+            constexpr bool has_kw_only_args = any_of<std::is_same<kw_only, Extra>...>::value,
+                           has_pos_only_args = any_of<std::is_same<pos_only, Extra>...>::value,
+                           has_arg_annotations = any_of<is_keyword<Extra>...>::value;
+            static_assert(has_arg_annotations || !has_kw_only_args,
+                          "py::kw_only requires the use of argument annotations");
+            static_assert(has_arg_annotations || !has_pos_only_args,
+                          "py::pos_only requires the use of argument annotations (for docstrings "
+                          "and aligning the annotations to the argument)");
+
+            static_assert(constexpr_sum(is_kw_only<Extra>::value...) <= 1,
+                          "py::kw_only may be specified only once");
+            static_assert(constexpr_sum(is_pos_only<Extra>::value...) <= 1,
+                          "py::pos_only may be specified only once");
+            constexpr auto kw_only_pos = constexpr_first<is_kw_only, Extra...>();
+            constexpr auto pos_only_pos = constexpr_first<is_pos_only, Extra...>();
+            static_assert(!(has_kw_only_args && has_pos_only_args) || pos_only_pos < kw_only_pos,
+                          "py::pos_only must come before py::kw_only");
+        }
+
+        /* Generate a readable signature describing the function's arguments and return
+           value types */
+        static constexpr auto signature
+            = const_name("(") + cast_in::arg_names + const_name(") -> ") + cast_out::name;
+        PYBIND11_DESCR_CONSTEXPR auto types = decltype(signature)::types();
+
+        /* Register the function with Python from generic (non-templated) code */
+        // Pass on the ownership over the `unique_rec` to `initialize_generic`. `rec` stays valid.
+        initialize_generic(std::move(unique_rec), signature.text, types.data(), sizeof...(Args));
+
+        /* Stash some additional information used by an important optimization in 'functional.h' */
+        using FunctionType = Return (*)(Args...);
+        constexpr bool is_function_ptr
+            = std::is_convertible<Func, FunctionType>::value && sizeof(capture) == sizeof(void *);
+        if (is_function_ptr) {
+            rec->is_stateless = true;
+            rec->data[1]
+                = const_cast<void *>(reinterpret_cast<const void *>(&typeid(FunctionType)));
+        }
+    }
+
+    // Utility class that keeps track of all duplicated strings, and cleans them up in its
+    // destructor, unless they are released. Basically a RAII-solution to deal with exceptions
+    // along the way.
+    class strdup_guard {
+    public:
+        strdup_guard() = default;
+        strdup_guard(const strdup_guard &) = delete;
+        strdup_guard &operator=(const strdup_guard &) = delete;
+
+        ~strdup_guard() {
+            for (auto *s : strings) {
+                std::free(s);
+            }
+        }
+        char *operator()(const char *s) {
+            auto *t = PYBIND11_COMPAT_STRDUP(s);
+            strings.push_back(t);
+            return t;
+        }
+        void release() { strings.clear(); }
+
+    private:
+        std::vector<char *> strings;
+    };
+
+    /// Register a function call with Python (generic non-templated code goes here)
+    void initialize_generic(unique_function_record &&unique_rec,
+                            const char *text,
+                            const std::type_info *const *types,
+                            size_t args) {
+        // Do NOT receive `unique_rec` by value. If this function fails to move out the unique_ptr,
+        // we do not want this to destruct the pointer. `initialize` (the caller) still relies on
+        // the pointee being alive after this call. Only move out if a `capsule` is going to keep
+        // it alive.
+        auto *rec = unique_rec.get();
+
+        // Keep track of strdup'ed strings, and clean them up as long as the function's capsule
+        // has not taken ownership yet (when `unique_rec.release()` is called).
+        // Note: This cannot easily be fixed by a `unique_ptr` with custom deleter, because the
+        // strings are only referenced before strdup'ing. So only *after* the following block could
+        // `destruct` safely be called, but even then, `repr` could still throw in the middle of
+        // copying all strings.
+        strdup_guard guarded_strdup;
+
+        /* Create copies of all referenced C-style strings */
+        rec->name = guarded_strdup(rec->name ? rec->name : "");
+        if (rec->doc) {
+            rec->doc = guarded_strdup(rec->doc);
+        }
+        for (auto &a : rec->args) {
+            if (a.name) {
+                a.name = guarded_strdup(a.name);
+            }
+            if (a.descr) {
+                a.descr = guarded_strdup(a.descr);
+            } else if (a.value) {
+                a.descr = guarded_strdup(repr(a.value).cast<std::string>().c_str());
+            }
+        }
+
+        rec->is_constructor = (std::strcmp(rec->name, "__init__") == 0)
+                              || (std::strcmp(rec->name, "__setstate__") == 0);
+
+#if defined(PYBIND11_DETAILED_ERROR_MESSAGES) && !defined(PYBIND11_DISABLE_NEW_STYLE_INIT_WARNING)
+        if (rec->is_constructor && !rec->is_new_style_constructor) {
+            const auto class_name
+                = detail::get_fully_qualified_tp_name((PyTypeObject *) rec->scope.ptr());
+            const auto func_name = std::string(rec->name);
+            PyErr_WarnEx(PyExc_FutureWarning,
+                         ("pybind11-bound class '" + class_name
+                          + "' is using an old-style "
+                            "placement-new '"
+                          + func_name
+                          + "' which has been deprecated. See "
+                            "the upgrade guide in pybind11's docs. This message is only visible "
+                            "when compiled in debug mode.")
+                             .c_str(),
+                         0);
+        }
+#endif
+
+        /* Generate a proper function signature */
+        std::string signature;
+        size_t type_index = 0, arg_index = 0;
+        bool is_starred = false;
+        for (const auto *pc = text; *pc != '\0'; ++pc) {
+            const auto c = *pc;
+
+            if (c == '{') {
+                // Write arg name for everything except *args and **kwargs.
+                is_starred = *(pc + 1) == '*';
+                if (is_starred) {
+                    continue;
+                }
+                // Separator for keyword-only arguments, placed before the kw
+                // arguments start (unless we are already putting an *args)
+                if (!rec->has_args && arg_index == rec->nargs_pos) {
+                    signature += "*, ";
+                }
+                if (arg_index < rec->args.size() && rec->args[arg_index].name) {
+                    signature += rec->args[arg_index].name;
+                } else if (arg_index == 0 && rec->is_method) {
+                    signature += "self";
+                } else {
+                    signature += "arg" + std::to_string(arg_index - (rec->is_method ? 1 : 0));
+                }
+                signature += ": ";
+            } else if (c == '}') {
+                // Write default value if available.
+                if (!is_starred && arg_index < rec->args.size() && rec->args[arg_index].descr) {
+                    signature += " = ";
+                    signature += rec->args[arg_index].descr;
+                }
+                // Separator for positional-only arguments (placed after the
+                // argument, rather than before like *
+                if (rec->nargs_pos_only > 0 && (arg_index + 1) == rec->nargs_pos_only) {
+                    signature += ", /";
+                }
+                if (!is_starred) {
+                    arg_index++;
+                }
+            } else if (c == '%') {
+                const std::type_info *t = types[type_index++];
+                if (!t) {
+                    pybind11_fail("Internal error while parsing type signature (1)");
+                }
+                if (auto *tinfo = detail::get_type_info(*t)) {
+                    handle th((PyObject *) tinfo->type);
+                    signature += th.attr("__module__").cast<std::string>() + "."
+                                 + th.attr("__qualname__").cast<std::string>();
+                } else if (rec->is_new_style_constructor && arg_index == 0) {
+                    // A new-style `__init__` takes `self` as `value_and_holder`.
+                    // Rewrite it to the proper class type.
+                    signature += rec->scope.attr("__module__").cast<std::string>() + "."
+                                 + rec->scope.attr("__qualname__").cast<std::string>();
+                } else {
+                    std::string tname(t->name());
+                    detail::clean_type_id(tname);
+                    signature += tname;
+                }
+            } else {
+                signature += c;
+            }
+        }
+
+        if (arg_index != args - rec->has_args - rec->has_kwargs || types[type_index] != nullptr) {
+            pybind11_fail("Internal error while parsing type signature (2)");
+        }
+
+        rec->signature = guarded_strdup(signature.c_str());
+        rec->args.shrink_to_fit();
+        rec->nargs = (std::uint16_t) args;
+
+        if (rec->sibling && PYBIND11_INSTANCE_METHOD_CHECK(rec->sibling.ptr())) {
+            rec->sibling = PYBIND11_INSTANCE_METHOD_GET_FUNCTION(rec->sibling.ptr());
+        }
+
+        detail::function_record *chain = nullptr, *chain_start = rec;
+        if (rec->sibling) {
+            if (PyCFunction_Check(rec->sibling.ptr())) {
+                auto *self = PyCFunction_GET_SELF(rec->sibling.ptr());
+                if (!isinstance<capsule>(self)) {
+                    chain = nullptr;
+                } else {
+                    auto rec_capsule = reinterpret_borrow<capsule>(self);
+                    if (detail::is_function_record_capsule(rec_capsule)) {
+                        chain = rec_capsule.get_pointer<detail::function_record>();
+                        /* Never append a method to an overload chain of a parent class;
+                           instead, hide the parent's overloads in this case */
+                        if (!chain->scope.is(rec->scope)) {
+                            chain = nullptr;
+                        }
+                    } else {
+                        chain = nullptr;
+                    }
+                }
+            }
+            // Don't trigger for things like the default __init__, which are wrapper_descriptors
+            // that we are intentionally replacing
+            else if (!rec->sibling.is_none() && rec->name[0] != '_') {
+                pybind11_fail("Cannot overload existing non-function object \""
+                              + std::string(rec->name) + "\" with a function of the same name");
+            }
+        }
+
+        if (!chain) {
+            /* No existing overload was found, create a new function object */
+            rec->def = new PyMethodDef();
+            std::memset(rec->def, 0, sizeof(PyMethodDef));
+            rec->def->ml_name = rec->name;
+            rec->def->ml_meth
+                = reinterpret_cast<PyCFunction>(reinterpret_cast<void (*)()>(dispatcher));
+            rec->def->ml_flags = METH_VARARGS | METH_KEYWORDS;
+
+            capsule rec_capsule(unique_rec.release(),
+                                [](void *ptr) { destruct((detail::function_record *) ptr); });
+            rec_capsule.set_name(detail::get_function_record_capsule_name());
+            guarded_strdup.release();
+
+            object scope_module;
+            if (rec->scope) {
+                if (hasattr(rec->scope, "__module__")) {
+                    scope_module = rec->scope.attr("__module__");
+                } else if (hasattr(rec->scope, "__name__")) {
+                    scope_module = rec->scope.attr("__name__");
+                }
+            }
+
+            m_ptr = PyCFunction_NewEx(rec->def, rec_capsule.ptr(), scope_module.ptr());
+            if (!m_ptr) {
+                pybind11_fail("cpp_function::cpp_function(): Could not allocate function object");
+            }
+        } else {
+            /* Append at the beginning or end of the overload chain */
+            m_ptr = rec->sibling.ptr();
+            inc_ref();
+            if (chain->is_method != rec->is_method) {
+                pybind11_fail(
+                    "overloading a method with both static and instance methods is not supported; "
+#if !defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+                    "#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for more "
+                    "details"
+#else
+                    "error while attempting to bind "
+                    + std::string(rec->is_method ? "instance" : "static") + " method "
+                    + std::string(pybind11::str(rec->scope.attr("__name__"))) + "."
+                    + std::string(rec->name) + signature
+#endif
+                );
+            }
+
+            if (rec->prepend) {
+                // Beginning of chain; we need to replace the capsule's current head-of-the-chain
+                // pointer with this one, then make this one point to the previous head of the
+                // chain.
+                chain_start = rec;
+                rec->next = chain;
+                auto rec_capsule
+                    = reinterpret_borrow<capsule>(((PyCFunctionObject *) m_ptr)->m_self);
+                rec_capsule.set_pointer(unique_rec.release());
+                guarded_strdup.release();
+            } else {
+                // Or end of chain (normal behavior)
+                chain_start = chain;
+                while (chain->next) {
+                    chain = chain->next;
+                }
+                chain->next = unique_rec.release();
+                guarded_strdup.release();
+            }
+        }
+
+        std::string signatures;
+        int index = 0;
+        /* Create a nice pydoc rec including all signatures and
+           docstrings of the functions in the overload chain */
+        if (chain && options::show_function_signatures()) {
+            // First a generic signature
+            signatures += rec->name;
+            signatures += "(*args, **kwargs)\n";
+            signatures += "Overloaded function.\n\n";
+        }
+        // Then specific overload signatures
+        bool first_user_def = true;
+        for (auto *it = chain_start; it != nullptr; it = it->next) {
+            if (options::show_function_signatures()) {
+                if (index > 0) {
+                    signatures += '\n';
+                }
+                if (chain) {
+                    signatures += std::to_string(++index) + ". ";
+                }
+                signatures += rec->name;
+                signatures += it->signature;
+                signatures += '\n';
+            }
+            if (it->doc && it->doc[0] != '\0' && options::show_user_defined_docstrings()) {
+                // If we're appending another docstring, and aren't printing function signatures,
+                // we need to append a newline first:
+                if (!options::show_function_signatures()) {
+                    if (first_user_def) {
+                        first_user_def = false;
+                    } else {
+                        signatures += '\n';
+                    }
+                }
+                if (options::show_function_signatures()) {
+                    signatures += '\n';
+                }
+                signatures += it->doc;
+                if (options::show_function_signatures()) {
+                    signatures += '\n';
+                }
+            }
+        }
+
+        /* Install docstring */
+        auto *func = (PyCFunctionObject *) m_ptr;
+        std::free(const_cast<char *>(func->m_ml->ml_doc));
+        // Install docstring if it's non-empty (when at least one option is enabled)
+        func->m_ml->ml_doc
+            = signatures.empty() ? nullptr : PYBIND11_COMPAT_STRDUP(signatures.c_str());
+
+        if (rec->is_method) {
+            m_ptr = PYBIND11_INSTANCE_METHOD_NEW(m_ptr, rec->scope.ptr());
+            if (!m_ptr) {
+                pybind11_fail(
+                    "cpp_function::cpp_function(): Could not allocate instance method object");
+            }
+            Py_DECREF(func);
+        }
+    }
+
+    /// When a cpp_function is GCed, release any memory allocated by pybind11
+    static void destruct(detail::function_record *rec, bool free_strings = true) {
+// If on Python 3.9, check the interpreter "MICRO" (patch) version.
+// If this is running on 3.9.0, we have to work around a bug.
+#if !defined(PYPY_VERSION) && PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION == 9
+        static bool is_zero = Py_GetVersion()[4] == '0';
+#endif
+
+        while (rec) {
+            detail::function_record *next = rec->next;
+            if (rec->free_data) {
+                rec->free_data(rec);
+            }
+            // During initialization, these strings might not have been copied yet,
+            // so they cannot be freed. Once the function has been created, they can.
+            // Check `make_function_record` for more details.
+            if (free_strings) {
+                std::free((char *) rec->name);
+                std::free((char *) rec->doc);
+                std::free((char *) rec->signature);
+                for (auto &arg : rec->args) {
+                    std::free(const_cast<char *>(arg.name));
+                    std::free(const_cast<char *>(arg.descr));
+                }
+            }
+            for (auto &arg : rec->args) {
+                arg.value.dec_ref();
+            }
+            if (rec->def) {
+                std::free(const_cast<char *>(rec->def->ml_doc));
+// Python 3.9.0 decref's these in the wrong order; rec->def
+// If loaded on 3.9.0, let these leak (use Python 3.9.1 at runtime to fix)
+// See https://github.com/python/cpython/pull/22670
+#if !defined(PYPY_VERSION) && PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION == 9
+                if (!is_zero) {
+                    delete rec->def;
+                }
+#else
+                delete rec->def;
+#endif
+            }
+            delete rec;
+            rec = next;
+        }
+    }
+
+    /// Main dispatch logic for calls to functions bound using pybind11
+    static PyObject *dispatcher(PyObject *self, PyObject *args_in, PyObject *kwargs_in) {
+        using namespace detail;
+        assert(isinstance<capsule>(self));
+
+        /* Iterator over the list of potentially admissible overloads */
+        const function_record *overloads = reinterpret_cast<function_record *>(
+                                  PyCapsule_GetPointer(self, get_function_record_capsule_name())),
+                              *it = overloads;
+        assert(overloads != nullptr);
+
+        /* Need to know how many arguments + keyword arguments there are to pick the right
+           overload */
+        const auto n_args_in = (size_t) PyTuple_GET_SIZE(args_in);
+
+        handle parent = n_args_in > 0 ? PyTuple_GET_ITEM(args_in, 0) : nullptr,
+               result = PYBIND11_TRY_NEXT_OVERLOAD;
+
+        auto self_value_and_holder = value_and_holder();
+        if (overloads->is_constructor) {
+            if (!parent
+                || !PyObject_TypeCheck(parent.ptr(), (PyTypeObject *) overloads->scope.ptr())) {
+                PyErr_SetString(
+                    PyExc_TypeError,
+                    "__init__(self, ...) called with invalid or missing `self` argument");
+                return nullptr;
+            }
+
+            auto *const tinfo = get_type_info((PyTypeObject *) overloads->scope.ptr());
+            auto *const pi = reinterpret_cast<instance *>(parent.ptr());
+            self_value_and_holder = pi->get_value_and_holder(tinfo, true);
+
+            // If this value is already registered it must mean __init__ is invoked multiple times;
+            // we really can't support that in C++, so just ignore the second __init__.
+            if (self_value_and_holder.instance_registered()) {
+                return none().release().ptr();
+            }
+        }
+
+        try {
+            // We do this in two passes: in the first pass, we load arguments with `convert=false`;
+            // in the second, we allow conversion (except for arguments with an explicit
+            // py::arg().noconvert()).  This lets us prefer calls without conversion, with
+            // conversion as a fallback.
+            std::vector<function_call> second_pass;
+
+            // However, if there are no overloads, we can just skip the no-convert pass entirely
+            const bool overloaded = it != nullptr && it->next != nullptr;
+
+            for (; it != nullptr; it = it->next) {
+
+                /* For each overload:
+                   1. Copy all positional arguments we were given, also checking to make sure that
+                      named positional arguments weren't *also* specified via kwarg.
+                   2. If we weren't given enough, try to make up the omitted ones by checking
+                      whether they were provided by a kwarg matching the `py::arg("name")` name. If
+                      so, use it (and remove it from kwargs); if not, see if the function binding
+                      provided a default that we can use.
+                   3. Ensure that either all keyword arguments were "consumed", or that the
+                   function takes a kwargs argument to accept unconsumed kwargs.
+                   4. Any positional arguments still left get put into a tuple (for args), and any
+                      leftover kwargs get put into a dict.
+                   5. Pack everything into a vector; if we have py::args or py::kwargs, they are an
+                      extra tuple or dict at the end of the positional arguments.
+                   6. Call the function call dispatcher (function_record::impl)
+
+                   If one of these fail, move on to the next overload and keep trying until we get
+                   a result other than PYBIND11_TRY_NEXT_OVERLOAD.
+                 */
+
+                const function_record &func = *it;
+                size_t num_args = func.nargs; // Number of positional arguments that we need
+                if (func.has_args) {
+                    --num_args; // (but don't count py::args
+                }
+                if (func.has_kwargs) {
+                    --num_args; //  or py::kwargs)
+                }
+                size_t pos_args = func.nargs_pos;
+
+                if (!func.has_args && n_args_in > pos_args) {
+                    continue; // Too many positional arguments for this overload
+                }
+
+                if (n_args_in < pos_args && func.args.size() < pos_args) {
+                    continue; // Not enough positional arguments given, and not enough defaults to
+                              // fill in the blanks
+                }
+
+                function_call call(func, parent);
+
+                // Protect std::min with parentheses
+                size_t args_to_copy = (std::min)(pos_args, n_args_in);
+                size_t args_copied = 0;
+
+                // 0. Inject new-style `self` argument
+                if (func.is_new_style_constructor) {
+                    // The `value` may have been preallocated by an old-style `__init__`
+                    // if it was a preceding candidate for overload resolution.
+                    if (self_value_and_holder) {
+                        self_value_and_holder.type->dealloc(self_value_and_holder);
+                    }
+
+                    call.init_self = PyTuple_GET_ITEM(args_in, 0);
+                    call.args.emplace_back(reinterpret_cast<PyObject *>(&self_value_and_holder));
+                    call.args_convert.push_back(false);
+                    ++args_copied;
+                }
+
+                // 1. Copy any position arguments given.
+                bool bad_arg = false;
+                for (; args_copied < args_to_copy; ++args_copied) {
+                    const argument_record *arg_rec
+                        = args_copied < func.args.size() ? &func.args[args_copied] : nullptr;
+                    if (kwargs_in && arg_rec && arg_rec->name
+                        && dict_getitemstring(kwargs_in, arg_rec->name)) {
+                        bad_arg = true;
+                        break;
+                    }
+
+                    handle arg(PyTuple_GET_ITEM(args_in, args_copied));
+                    if (arg_rec && !arg_rec->none && arg.is_none()) {
+                        bad_arg = true;
+                        break;
+                    }
+                    call.args.push_back(arg);
+                    call.args_convert.push_back(arg_rec ? arg_rec->convert : true);
+                }
+                if (bad_arg) {
+                    continue; // Maybe it was meant for another overload (issue #688)
+                }
+
+                // Keep track of how many position args we copied out in case we need to come back
+                // to copy the rest into a py::args argument.
+                size_t positional_args_copied = args_copied;
+
+                // We'll need to copy this if we steal some kwargs for defaults
+                dict kwargs = reinterpret_borrow<dict>(kwargs_in);
+
+                // 1.5. Fill in any missing pos_only args from defaults if they exist
+                if (args_copied < func.nargs_pos_only) {
+                    for (; args_copied < func.nargs_pos_only; ++args_copied) {
+                        const auto &arg_rec = func.args[args_copied];
+                        handle value;
+
+                        if (arg_rec.value) {
+                            value = arg_rec.value;
+                        }
+                        if (value) {
+                            call.args.push_back(value);
+                            call.args_convert.push_back(arg_rec.convert);
+                        } else {
+                            break;
+                        }
+                    }
+
+                    if (args_copied < func.nargs_pos_only) {
+                        continue; // Not enough defaults to fill the positional arguments
+                    }
+                }
+
+                // 2. Check kwargs and, failing that, defaults that may help complete the list
+                if (args_copied < num_args) {
+                    bool copied_kwargs = false;
+
+                    for (; args_copied < num_args; ++args_copied) {
+                        const auto &arg_rec = func.args[args_copied];
+
+                        handle value;
+                        if (kwargs_in && arg_rec.name) {
+                            value = dict_getitemstring(kwargs.ptr(), arg_rec.name);
+                        }
+
+                        if (value) {
+                            // Consume a kwargs value
+                            if (!copied_kwargs) {
+                                kwargs = reinterpret_steal<dict>(PyDict_Copy(kwargs.ptr()));
+                                copied_kwargs = true;
+                            }
+                            if (PyDict_DelItemString(kwargs.ptr(), arg_rec.name) == -1) {
+                                throw error_already_set();
+                            }
+                        } else if (arg_rec.value) {
+                            value = arg_rec.value;
+                        }
+
+                        if (!arg_rec.none && value.is_none()) {
+                            break;
+                        }
+
+                        if (value) {
+                            // If we're at the py::args index then first insert a stub for it to be
+                            // replaced later
+                            if (func.has_args && call.args.size() == func.nargs_pos) {
+                                call.args.push_back(none());
+                            }
+
+                            call.args.push_back(value);
+                            call.args_convert.push_back(arg_rec.convert);
+                        } else {
+                            break;
+                        }
+                    }
+
+                    if (args_copied < num_args) {
+                        continue; // Not enough arguments, defaults, or kwargs to fill the
+                                  // positional arguments
+                    }
+                }
+
+                // 3. Check everything was consumed (unless we have a kwargs arg)
+                if (kwargs && !kwargs.empty() && !func.has_kwargs) {
+                    continue; // Unconsumed kwargs, but no py::kwargs argument to accept them
+                }
+
+                // 4a. If we have a py::args argument, create a new tuple with leftovers
+                if (func.has_args) {
+                    tuple extra_args;
+                    if (args_to_copy == 0) {
+                        // We didn't copy out any position arguments from the args_in tuple, so we
+                        // can reuse it directly without copying:
+                        extra_args = reinterpret_borrow<tuple>(args_in);
+                    } else if (positional_args_copied >= n_args_in) {
+                        extra_args = tuple(0);
+                    } else {
+                        size_t args_size = n_args_in - positional_args_copied;
+                        extra_args = tuple(args_size);
+                        for (size_t i = 0; i < args_size; ++i) {
+                            extra_args[i] = PyTuple_GET_ITEM(args_in, positional_args_copied + i);
+                        }
+                    }
+                    if (call.args.size() <= func.nargs_pos) {
+                        call.args.push_back(extra_args);
+                    } else {
+                        call.args[func.nargs_pos] = extra_args;
+                    }
+                    call.args_convert.push_back(false);
+                    call.args_ref = std::move(extra_args);
+                }
+
+                // 4b. If we have a py::kwargs, pass on any remaining kwargs
+                if (func.has_kwargs) {
+                    if (!kwargs.ptr()) {
+                        kwargs = dict(); // If we didn't get one, send an empty one
+                    }
+                    call.args.push_back(kwargs);
+                    call.args_convert.push_back(false);
+                    call.kwargs_ref = std::move(kwargs);
+                }
+
+// 5. Put everything in a vector.  Not technically step 5, we've been building it
+// in `call.args` all along.
+#if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
+                if (call.args.size() != func.nargs || call.args_convert.size() != func.nargs) {
+                    pybind11_fail("Internal error: function call dispatcher inserted wrong number "
+                                  "of arguments!");
+                }
+#endif
+
+                std::vector<bool> second_pass_convert;
+                if (overloaded) {
+                    // We're in the first no-convert pass, so swap out the conversion flags for a
+                    // set of all-false flags.  If the call fails, we'll swap the flags back in for
+                    // the conversion-allowed call below.
+                    second_pass_convert.resize(func.nargs, false);
+                    call.args_convert.swap(second_pass_convert);
+                }
+
+                // 6. Call the function.
+                try {
+                    loader_life_support guard{};
+                    result = func.impl(call);
+                } catch (reference_cast_error &) {
+                    result = PYBIND11_TRY_NEXT_OVERLOAD;
+                }
+
+                if (result.ptr() != PYBIND11_TRY_NEXT_OVERLOAD) {
+                    break;
+                }
+
+                if (overloaded) {
+                    // The (overloaded) call failed; if the call has at least one argument that
+                    // permits conversion (i.e. it hasn't been explicitly specified `.noconvert()`)
+                    // then add this call to the list of second pass overloads to try.
+                    for (size_t i = func.is_method ? 1 : 0; i < pos_args; i++) {
+                        if (second_pass_convert[i]) {
+                            // Found one: swap the converting flags back in and store the call for
+                            // the second pass.
+                            call.args_convert.swap(second_pass_convert);
+                            second_pass.push_back(std::move(call));
+                            break;
+                        }
+                    }
+                }
+            }
+
+            if (overloaded && !second_pass.empty() && result.ptr() == PYBIND11_TRY_NEXT_OVERLOAD) {
+                // The no-conversion pass finished without success, try again with conversion
+                // allowed
+                for (auto &call : second_pass) {
+                    try {
+                        loader_life_support guard{};
+                        result = call.func.impl(call);
+                    } catch (reference_cast_error &) {
+                        result = PYBIND11_TRY_NEXT_OVERLOAD;
+                    }
+
+                    if (result.ptr() != PYBIND11_TRY_NEXT_OVERLOAD) {
+                        // The error reporting logic below expects 'it' to be valid, as it would be
+                        // if we'd encountered this failure in the first-pass loop.
+                        if (!result) {
+                            it = &call.func;
+                        }
+                        break;
+                    }
+                }
+            }
+        } catch (error_already_set &e) {
+            e.restore();
+            return nullptr;
+#ifdef __GLIBCXX__
+        } catch (abi::__forced_unwind &) {
+            throw;
+#endif
+        } catch (...) {
+            /* When an exception is caught, give each registered exception
+               translator a chance to translate it to a Python exception. First
+               all module-local translators will be tried in reverse order of
+               registration. If none of the module-locale translators handle
+               the exception (or there are no module-locale translators) then
+               the global translators will be tried, also in reverse order of
+               registration.
+
+               A translator may choose to do one of the following:
+
+                - catch the exception and call PyErr_SetString or PyErr_SetObject
+                  to set a standard (or custom) Python exception, or
+                - do nothing and let the exception fall through to the next translator, or
+                - delegate translation to the next translator by throwing a new type of exception.
+             */
+
+            auto &local_exception_translators
+                = get_local_internals().registered_exception_translators;
+            if (detail::apply_exception_translators(local_exception_translators)) {
+                return nullptr;
+            }
+            auto &exception_translators = get_internals().registered_exception_translators;
+            if (detail::apply_exception_translators(exception_translators)) {
+                return nullptr;
+            }
+
+            PyErr_SetString(PyExc_SystemError,
+                            "Exception escaped from default exception translator!");
+            return nullptr;
+        }
+
+        auto append_note_if_missing_header_is_suspected = [](std::string &msg) {
+            if (msg.find("std::") != std::string::npos) {
+                msg += "\n\n"
+                       "Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,\n"
+                       "<pybind11/functional.h>, <pybind11/chrono.h>, etc. Some automatic\n"
+                       "conversions are optional and require extra headers to be included\n"
+                       "when compiling your pybind11 module.";
+            }
+        };
+
+        if (result.ptr() == PYBIND11_TRY_NEXT_OVERLOAD) {
+            if (overloads->is_operator) {
+                return handle(Py_NotImplemented).inc_ref().ptr();
+            }
+
+            std::string msg = std::string(overloads->name) + "(): incompatible "
+                              + std::string(overloads->is_constructor ? "constructor" : "function")
+                              + " arguments. The following argument types are supported:\n";
+
+            int ctr = 0;
+            for (const function_record *it2 = overloads; it2 != nullptr; it2 = it2->next) {
+                msg += "    " + std::to_string(++ctr) + ". ";
+
+                bool wrote_sig = false;
+                if (overloads->is_constructor) {
+                    // For a constructor, rewrite `(self: Object, arg0, ...) -> NoneType` as
+                    // `Object(arg0, ...)`
+                    std::string sig = it2->signature;
+                    size_t start = sig.find('(') + 7; // skip "(self: "
+                    if (start < sig.size()) {
+                        // End at the , for the next argument
+                        size_t end = sig.find(", "), next = end + 2;
+                        size_t ret = sig.rfind(" -> ");
+                        // Or the ), if there is no comma:
+                        if (end >= sig.size()) {
+                            next = end = sig.find(')');
+                        }
+                        if (start < end && next < sig.size()) {
+                            msg.append(sig, start, end - start);
+                            msg += '(';
+                            msg.append(sig, next, ret - next);
+                            wrote_sig = true;
+                        }
+                    }
+                }
+                if (!wrote_sig) {
+                    msg += it2->signature;
+                }
+
+                msg += '\n';
+            }
+            msg += "\nInvoked with: ";
+            auto args_ = reinterpret_borrow<tuple>(args_in);
+            bool some_args = false;
+            for (size_t ti = overloads->is_constructor ? 1 : 0; ti < args_.size(); ++ti) {
+                if (!some_args) {
+                    some_args = true;
+                } else {
+                    msg += ", ";
+                }
+                try {
+                    msg += pybind11::repr(args_[ti]);
+                } catch (const error_already_set &) {
+                    msg += "<repr raised Error>";
+                }
+            }
+            if (kwargs_in) {
+                auto kwargs = reinterpret_borrow<dict>(kwargs_in);
+                if (!kwargs.empty()) {
+                    if (some_args) {
+                        msg += "; ";
+                    }
+                    msg += "kwargs: ";
+                    bool first = true;
+                    for (auto kwarg : kwargs) {
+                        if (first) {
+                            first = false;
+                        } else {
+                            msg += ", ";
+                        }
+                        msg += pybind11::str("{}=").format(kwarg.first);
+                        try {
+                            msg += pybind11::repr(kwarg.second);
+                        } catch (const error_already_set &) {
+                            msg += "<repr raised Error>";
+                        }
+                    }
+                }
+            }
+
+            append_note_if_missing_header_is_suspected(msg);
+            // Attach additional error info to the exception if supported
+            if (PyErr_Occurred()) {
+                // #HelpAppreciated: unit test coverage for this branch.
+                raise_from(PyExc_TypeError, msg.c_str());
+                return nullptr;
+            }
+            PyErr_SetString(PyExc_TypeError, msg.c_str());
+            return nullptr;
+        }
+        if (!result) {
+            std::string msg = "Unable to convert function return value to a "
+                              "Python type! The signature was\n\t";
+            msg += it->signature;
+            append_note_if_missing_header_is_suspected(msg);
+            // Attach additional error info to the exception if supported
+            if (PyErr_Occurred()) {
+                raise_from(PyExc_TypeError, msg.c_str());
+                return nullptr;
+            }
+            PyErr_SetString(PyExc_TypeError, msg.c_str());
+            return nullptr;
+        }
+        if (overloads->is_constructor && !self_value_and_holder.holder_constructed()) {
+            auto *pi = reinterpret_cast<instance *>(parent.ptr());
+            self_value_and_holder.type->init_instance(pi, nullptr);
+        }
+        return result.ptr();
+    }
+};
+
+/// Wrapper for Python extension modules
+class module_ : public object {
+public:
+    PYBIND11_OBJECT_DEFAULT(module_, object, PyModule_Check)
+
+    /// Create a new top-level Python module with the given name and docstring
+    PYBIND11_DEPRECATED("Use PYBIND11_MODULE or module_::create_extension_module instead")
+    explicit module_(const char *name, const char *doc = nullptr) {
+        *this = create_extension_module(name, doc, new PyModuleDef());
+    }
+
+    /** \rst
+        Create Python binding for a new function within the module scope. ``Func``
+        can be a plain C++ function, a function pointer, or a lambda function. For
+        details on the ``Extra&& ... extra`` argument, see section :ref:`extras`.
+    \endrst */
+    template <typename Func, typename... Extra>
+    module_ &def(const char *name_, Func &&f, const Extra &...extra) {
+        cpp_function func(std::forward<Func>(f),
+                          name(name_),
+                          scope(*this),
+                          sibling(getattr(*this, name_, none())),
+                          extra...);
+        // NB: allow overwriting here because cpp_function sets up a chain with the intention of
+        // overwriting (and has already checked internally that it isn't overwriting
+        // non-functions).
+        add_object(name_, func, true /* overwrite */);
+        return *this;
+    }
+
+    /** \rst
+        Create and return a new Python submodule with the given name and docstring.
+        This also works recursively, i.e.
+
+        .. code-block:: cpp
+
+            py::module_ m("example", "pybind11 example plugin");
+            py::module_ m2 = m.def_submodule("sub", "A submodule of 'example'");
+            py::module_ m3 = m2.def_submodule("subsub", "A submodule of 'example.sub'");
+    \endrst */
+    module_ def_submodule(const char *name, const char *doc = nullptr) {
+        const char *this_name = PyModule_GetName(m_ptr);
+        if (this_name == nullptr) {
+            throw error_already_set();
+        }
+        std::string full_name = std::string(this_name) + '.' + name;
+        handle submodule = PyImport_AddModule(full_name.c_str());
+        if (!submodule) {
+            throw error_already_set();
+        }
+        auto result = reinterpret_borrow<module_>(submodule);
+        if (doc && options::show_user_defined_docstrings()) {
+            result.attr("__doc__") = pybind11::str(doc);
+        }
+        attr(name) = result;
+        return result;
+    }
+
+    /// Import and return a module or throws `error_already_set`.
+    static module_ import(const char *name) {
+        PyObject *obj = PyImport_ImportModule(name);
+        if (!obj) {
+            throw error_already_set();
+        }
+        return reinterpret_steal<module_>(obj);
+    }
+
+    /// Reload the module or throws `error_already_set`.
+    void reload() {
+        PyObject *obj = PyImport_ReloadModule(ptr());
+        if (!obj) {
+            throw error_already_set();
+        }
+        *this = reinterpret_steal<module_>(obj);
+    }
+
+    /** \rst
+        Adds an object to the module using the given name.  Throws if an object with the given name
+        already exists.
+
+        ``overwrite`` should almost always be false: attempting to overwrite objects that pybind11
+        has established will, in most cases, break things.
+    \endrst */
+    PYBIND11_NOINLINE void add_object(const char *name, handle obj, bool overwrite = false) {
+        if (!overwrite && hasattr(*this, name)) {
+            pybind11_fail(
+                "Error during initialization: multiple incompatible definitions with name \""
+                + std::string(name) + "\"");
+        }
+
+        PyModule_AddObject(ptr(), name, obj.inc_ref().ptr() /* steals a reference */);
+    }
+
+    using module_def = PyModuleDef; // TODO: Can this be removed (it was needed only for Python 2)?
+
+    /** \rst
+        Create a new top-level module that can be used as the main module of a C extension.
+
+        ``def`` should point to a statically allocated module_def.
+    \endrst */
+    static module_ create_extension_module(const char *name, const char *doc, module_def *def) {
+        // module_def is PyModuleDef
+        // Placement new (not an allocation).
+        def = new (def)
+            PyModuleDef{/* m_base */ PyModuleDef_HEAD_INIT,
+                        /* m_name */ name,
+                        /* m_doc */ options::show_user_defined_docstrings() ? doc : nullptr,
+                        /* m_size */ -1,
+                        /* m_methods */ nullptr,
+                        /* m_slots */ nullptr,
+                        /* m_traverse */ nullptr,
+                        /* m_clear */ nullptr,
+                        /* m_free */ nullptr};
+        auto *m = PyModule_Create(def);
+        if (m == nullptr) {
+            if (PyErr_Occurred()) {
+                throw error_already_set();
+            }
+            pybind11_fail("Internal error in module_::create_extension_module()");
+        }
+        // TODO: Should be reinterpret_steal for Python 3, but Python also steals it again when
+        //       returned from PyInit_...
+        //       For Python 2, reinterpret_borrow was correct.
+        return reinterpret_borrow<module_>(m);
+    }
+};
+
+// When inside a namespace (or anywhere as long as it's not the first item on a line),
+// C++20 allows "module" to be used. This is provided for backward compatibility, and for
+// simplicity, if someone wants to use py::module for example, that is perfectly safe.
+using module = module_;
+
+/// \ingroup python_builtins
+/// Return a dictionary representing the global variables in the current execution frame,
+/// or ``__main__.__dict__`` if there is no frame (usually when the interpreter is embedded).
+inline dict globals() {
+    PyObject *p = PyEval_GetGlobals();
+    return reinterpret_borrow<dict>(p ? p : module_::import("__main__").attr("__dict__").ptr());
+}
+
+template <typename... Args, typename = detail::enable_if_t<args_are_all_keyword_or_ds<Args...>()>>
+PYBIND11_DEPRECATED("make_simple_namespace should be replaced with "
+                    "py::module_::import(\"types\").attr(\"SimpleNamespace\") ")
+object make_simple_namespace(Args &&...args_) {
+    return module_::import("types").attr("SimpleNamespace")(std::forward<Args>(args_)...);
+}
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+/// Generic support for creating new Python heap types
+class generic_type : public object {
+public:
+    PYBIND11_OBJECT_DEFAULT(generic_type, object, PyType_Check)
+protected:
+    void initialize(const type_record &rec) {
+        if (rec.scope && hasattr(rec.scope, "__dict__")
+            && rec.scope.attr("__dict__").contains(rec.name)) {
+            pybind11_fail("generic_type: cannot initialize type \"" + std::string(rec.name)
+                          + "\": an object with that name is already defined");
+        }
+
+        if ((rec.module_local ? get_local_type_info(*rec.type) : get_global_type_info(*rec.type))
+            != nullptr) {
+            pybind11_fail("generic_type: type \"" + std::string(rec.name)
+                          + "\" is already registered!");
+        }
+
+        m_ptr = make_new_python_type(rec);
+
+        /* Register supplemental type information in C++ dict */
+        auto *tinfo = new detail::type_info();
+        tinfo->type = (PyTypeObject *) m_ptr;
+        tinfo->cpptype = rec.type;
+        tinfo->type_size = rec.type_size;
+        tinfo->type_align = rec.type_align;
+        tinfo->operator_new = rec.operator_new;
+        tinfo->holder_size_in_ptrs = size_in_ptrs(rec.holder_size);
+        tinfo->init_instance = rec.init_instance;
+        tinfo->dealloc = rec.dealloc;
+        tinfo->simple_type = true;
+        tinfo->simple_ancestors = true;
+        tinfo->default_holder = rec.default_holder;
+        tinfo->module_local = rec.module_local;
+
+        auto &internals = get_internals();
+        auto tindex = std::type_index(*rec.type);
+        tinfo->direct_conversions = &internals.direct_conversions[tindex];
+        if (rec.module_local) {
+            get_local_internals().registered_types_cpp[tindex] = tinfo;
+        } else {
+            internals.registered_types_cpp[tindex] = tinfo;
+        }
+        internals.registered_types_py[(PyTypeObject *) m_ptr] = {tinfo};
+
+        if (rec.bases.size() > 1 || rec.multiple_inheritance) {
+            mark_parents_nonsimple(tinfo->type);
+            tinfo->simple_ancestors = false;
+        } else if (rec.bases.size() == 1) {
+            auto *parent_tinfo = get_type_info((PyTypeObject *) rec.bases[0].ptr());
+            assert(parent_tinfo != nullptr);
+            bool parent_simple_ancestors = parent_tinfo->simple_ancestors;
+            tinfo->simple_ancestors = parent_simple_ancestors;
+            // The parent can no longer be a simple type if it has MI and has a child
+            parent_tinfo->simple_type = parent_tinfo->simple_type && parent_simple_ancestors;
+        }
+
+        if (rec.module_local) {
+            // Stash the local typeinfo and loader so that external modules can access it.
+            tinfo->module_local_load = &type_caster_generic::local_load;
+            setattr(m_ptr, PYBIND11_MODULE_LOCAL_ID, capsule(tinfo));
+        }
+    }
+
+    /// Helper function which tags all parents of a type using mult. inheritance
+    void mark_parents_nonsimple(PyTypeObject *value) {
+        auto t = reinterpret_borrow<tuple>(value->tp_bases);
+        for (handle h : t) {
+            auto *tinfo2 = get_type_info((PyTypeObject *) h.ptr());
+            if (tinfo2) {
+                tinfo2->simple_type = false;
+            }
+            mark_parents_nonsimple((PyTypeObject *) h.ptr());
+        }
+    }
+
+    void install_buffer_funcs(buffer_info *(*get_buffer)(PyObject *, void *),
+                              void *get_buffer_data) {
+        auto *type = (PyHeapTypeObject *) m_ptr;
+        auto *tinfo = detail::get_type_info(&type->ht_type);
+
+        if (!type->ht_type.tp_as_buffer) {
+            pybind11_fail("To be able to register buffer protocol support for the type '"
+                          + get_fully_qualified_tp_name(tinfo->type)
+                          + "' the associated class<>(..) invocation must "
+                            "include the pybind11::buffer_protocol() annotation!");
+        }
+
+        tinfo->get_buffer = get_buffer;
+        tinfo->get_buffer_data = get_buffer_data;
+    }
+
+    // rec_func must be set for either fget or fset.
+    void def_property_static_impl(const char *name,
+                                  handle fget,
+                                  handle fset,
+                                  detail::function_record *rec_func) {
+        const auto is_static = (rec_func != nullptr) && !(rec_func->is_method && rec_func->scope);
+        const auto has_doc = (rec_func != nullptr) && (rec_func->doc != nullptr)
+                             && pybind11::options::show_user_defined_docstrings();
+        auto property = handle(
+            (PyObject *) (is_static ? get_internals().static_property_type : &PyProperty_Type));
+        attr(name) = property(fget.ptr() ? fget : none(),
+                              fset.ptr() ? fset : none(),
+                              /*deleter*/ none(),
+                              pybind11::str(has_doc ? rec_func->doc : ""));
+    }
+};
+
+/// Set the pointer to operator new if it exists. The cast is needed because it can be overloaded.
+template <typename T,
+          typename = void_t<decltype(static_cast<void *(*) (size_t)>(T::operator new))>>
+void set_operator_new(type_record *r) {
+    r->operator_new = &T::operator new;
+}
+
+template <typename>
+void set_operator_new(...) {}
+
+template <typename T, typename SFINAE = void>
+struct has_operator_delete : std::false_type {};
+template <typename T>
+struct has_operator_delete<T, void_t<decltype(static_cast<void (*)(void *)>(T::operator delete))>>
+    : std::true_type {};
+template <typename T, typename SFINAE = void>
+struct has_operator_delete_size : std::false_type {};
+template <typename T>
+struct has_operator_delete_size<
+    T,
+    void_t<decltype(static_cast<void (*)(void *, size_t)>(T::operator delete))>> : std::true_type {
+};
+/// Call class-specific delete if it exists or global otherwise. Can also be an overload set.
+template <typename T, enable_if_t<has_operator_delete<T>::value, int> = 0>
+void call_operator_delete(T *p, size_t, size_t) {
+    T::operator delete(p);
+}
+template <typename T,
+          enable_if_t<!has_operator_delete<T>::value && has_operator_delete_size<T>::value, int>
+          = 0>
+void call_operator_delete(T *p, size_t s, size_t) {
+    T::operator delete(p, s);
+}
+
+inline void call_operator_delete(void *p, size_t s, size_t a) {
+    (void) s;
+    (void) a;
+#if defined(__cpp_aligned_new) && (!defined(_MSC_VER) || _MSC_VER >= 1912)
+    if (a > __STDCPP_DEFAULT_NEW_ALIGNMENT__) {
+#    ifdef __cpp_sized_deallocation
+        ::operator delete(p, s, std::align_val_t(a));
+#    else
+        ::operator delete(p, std::align_val_t(a));
+#    endif
+        return;
+    }
+#endif
+#ifdef __cpp_sized_deallocation
+    ::operator delete(p, s);
+#else
+    ::operator delete(p);
+#endif
+}
+
+inline void add_class_method(object &cls, const char *name_, const cpp_function &cf) {
+    cls.attr(cf.name()) = cf;
+    if (std::strcmp(name_, "__eq__") == 0 && !cls.attr("__dict__").contains("__hash__")) {
+        cls.attr("__hash__") = none();
+    }
+}
+
+PYBIND11_NAMESPACE_END(detail)
+
+/// Given a pointer to a member function, cast it to its `Derived` version.
+/// Forward everything else unchanged.
+template <typename /*Derived*/, typename F>
+auto method_adaptor(F &&f) -> decltype(std::forward<F>(f)) {
+    return std::forward<F>(f);
+}
+
+template <typename Derived, typename Return, typename Class, typename... Args>
+auto method_adaptor(Return (Class::*pmf)(Args...)) -> Return (Derived::*)(Args...) {
+    static_assert(
+        detail::is_accessible_base_of<Class, Derived>::value,
+        "Cannot bind an inaccessible base class method; use a lambda definition instead");
+    return pmf;
+}
+
+template <typename Derived, typename Return, typename Class, typename... Args>
+auto method_adaptor(Return (Class::*pmf)(Args...) const) -> Return (Derived::*)(Args...) const {
+    static_assert(
+        detail::is_accessible_base_of<Class, Derived>::value,
+        "Cannot bind an inaccessible base class method; use a lambda definition instead");
+    return pmf;
+}
+
+template <typename type_, typename... options>
+class class_ : public detail::generic_type {
+    template <typename T>
+    using is_holder = detail::is_holder_type<type_, T>;
+    template <typename T>
+    using is_subtype = detail::is_strict_base_of<type_, T>;
+    template <typename T>
+    using is_base = detail::is_strict_base_of<T, type_>;
+    // struct instead of using here to help MSVC:
+    template <typename T>
+    struct is_valid_class_option : detail::any_of<is_holder<T>, is_subtype<T>, is_base<T>> {};
+
+public:
+    using type = type_;
+    using type_alias = detail::exactly_one_t<is_subtype, void, options...>;
+    constexpr static bool has_alias = !std::is_void<type_alias>::value;
+    using holder_type = detail::exactly_one_t<is_holder, std::unique_ptr<type>, options...>;
+
+    static_assert(detail::all_of<is_valid_class_option<options>...>::value,
+                  "Unknown/invalid class_ template parameters provided");
+
+    static_assert(!has_alias || std::is_polymorphic<type>::value,
+                  "Cannot use an alias class with a non-polymorphic type");
+
+    PYBIND11_OBJECT(class_, generic_type, PyType_Check)
+
+    template <typename... Extra>
+    class_(handle scope, const char *name, const Extra &...extra) {
+        using namespace detail;
+
+        // MI can only be specified via class_ template options, not constructor parameters
+        static_assert(
+            none_of<is_pyobject<Extra>...>::value || // no base class arguments, or:
+                (constexpr_sum(is_pyobject<Extra>::value...) == 1 && // Exactly one base
+                 constexpr_sum(is_base<options>::value...) == 0 &&   // no template option bases
+                 // no multiple_inheritance attr
+                 none_of<std::is_same<multiple_inheritance, Extra>...>::value),
+            "Error: multiple inheritance bases must be specified via class_ template options");
+
+        type_record record;
+        record.scope = scope;
+        record.name = name;
+        record.type = &typeid(type);
+        record.type_size = sizeof(conditional_t<has_alias, type_alias, type>);
+        record.type_align = alignof(conditional_t<has_alias, type_alias, type> &);
+        record.holder_size = sizeof(holder_type);
+        record.init_instance = init_instance;
+        record.dealloc = dealloc;
+        record.default_holder = detail::is_instantiation<std::unique_ptr, holder_type>::value;
+
+        set_operator_new<type>(&record);
+
+        /* Register base classes specified via template arguments to class_, if any */
+        PYBIND11_EXPAND_SIDE_EFFECTS(add_base<options>(record));
+
+        /* Process optional arguments, if any */
+        process_attributes<Extra...>::init(extra..., &record);
+
+        generic_type::initialize(record);
+
+        if (has_alias) {
+            auto &instances = record.module_local ? get_local_internals().registered_types_cpp
+                                                  : get_internals().registered_types_cpp;
+            instances[std::type_index(typeid(type_alias))]
+                = instances[std::type_index(typeid(type))];
+        }
+    }
+
+    template <typename Base, detail::enable_if_t<is_base<Base>::value, int> = 0>
+    static void add_base(detail::type_record &rec) {
+        rec.add_base(typeid(Base), [](void *src) -> void * {
+            return static_cast<Base *>(reinterpret_cast<type *>(src));
+        });
+    }
+
+    template <typename Base, detail::enable_if_t<!is_base<Base>::value, int> = 0>
+    static void add_base(detail::type_record &) {}
+
+    template <typename Func, typename... Extra>
+    class_ &def(const char *name_, Func &&f, const Extra &...extra) {
+        cpp_function cf(method_adaptor<type>(std::forward<Func>(f)),
+                        name(name_),
+                        is_method(*this),
+                        sibling(getattr(*this, name_, none())),
+                        extra...);
+        add_class_method(*this, name_, cf);
+        return *this;
+    }
+
+    template <typename Func, typename... Extra>
+    class_ &def_static(const char *name_, Func &&f, const Extra &...extra) {
+        static_assert(!std::is_member_function_pointer<Func>::value,
+                      "def_static(...) called with a non-static member function pointer");
+        cpp_function cf(std::forward<Func>(f),
+                        name(name_),
+                        scope(*this),
+                        sibling(getattr(*this, name_, none())),
+                        extra...);
+        auto cf_name = cf.name();
+        attr(std::move(cf_name)) = staticmethod(std::move(cf));
+        return *this;
+    }
+
+    template <typename T, typename... Extra, detail::enable_if_t<T::op_enable_if_hook, int> = 0>
+    class_ &def(const T &op, const Extra &...extra) {
+        op.execute(*this, extra...);
+        return *this;
+    }
+
+    template <typename T, typename... Extra, detail::enable_if_t<T::op_enable_if_hook, int> = 0>
+    class_ &def_cast(const T &op, const Extra &...extra) {
+        op.execute_cast(*this, extra...);
+        return *this;
+    }
+
+    template <typename... Args, typename... Extra>
+    class_ &def(const detail::initimpl::constructor<Args...> &init, const Extra &...extra) {
+        PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(init);
+        init.execute(*this, extra...);
+        return *this;
+    }
+
+    template <typename... Args, typename... Extra>
+    class_ &def(const detail::initimpl::alias_constructor<Args...> &init, const Extra &...extra) {
+        PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100(init);
+        init.execute(*this, extra...);
+        return *this;
+    }
+
+    template <typename... Args, typename... Extra>
+    class_ &def(detail::initimpl::factory<Args...> &&init, const Extra &...extra) {
+        std::move(init).execute(*this, extra...);
+        return *this;
+    }
+
+    template <typename... Args, typename... Extra>
+    class_ &def(detail::initimpl::pickle_factory<Args...> &&pf, const Extra &...extra) {
+        std::move(pf).execute(*this, extra...);
+        return *this;
+    }
+
+    template <typename Func>
+    class_ &def_buffer(Func &&func) {
+        struct capture {
+            Func func;
+        };
+        auto *ptr = new capture{std::forward<Func>(func)};
+        install_buffer_funcs(
+            [](PyObject *obj, void *ptr) -> buffer_info * {
+                detail::make_caster<type> caster;
+                if (!caster.load(obj, false)) {
+                    return nullptr;
+                }
+                return new buffer_info(((capture *) ptr)->func(std::move(caster)));
+            },
+            ptr);
+        weakref(m_ptr, cpp_function([ptr](handle wr) {
+                    delete ptr;
+                    wr.dec_ref();
+                }))
+            .release();
+        return *this;
+    }
+
+    template <typename Return, typename Class, typename... Args>
+    class_ &def_buffer(Return (Class::*func)(Args...)) {
+        return def_buffer([func](type &obj) { return (obj.*func)(); });
+    }
+
+    template <typename Return, typename Class, typename... Args>
+    class_ &def_buffer(Return (Class::*func)(Args...) const) {
+        return def_buffer([func](const type &obj) { return (obj.*func)(); });
+    }
+
+    template <typename C, typename D, typename... Extra>
+    class_ &def_readwrite(const char *name, D C::*pm, const Extra &...extra) {
+        static_assert(std::is_same<C, type>::value || std::is_base_of<C, type>::value,
+                      "def_readwrite() requires a class member (or base class member)");
+        cpp_function fget([pm](const type &c) -> const D & { return c.*pm; }, is_method(*this)),
+            fset([pm](type &c, const D &value) { c.*pm = value; }, is_method(*this));
+        def_property(name, fget, fset, return_value_policy::reference_internal, extra...);
+        return *this;
+    }
+
+    template <typename C, typename D, typename... Extra>
+    class_ &def_readonly(const char *name, const D C::*pm, const Extra &...extra) {
+        static_assert(std::is_same<C, type>::value || std::is_base_of<C, type>::value,
+                      "def_readonly() requires a class member (or base class member)");
+        cpp_function fget([pm](const type &c) -> const D & { return c.*pm; }, is_method(*this));
+        def_property_readonly(name, fget, return_value_policy::reference_internal, extra...);
+        return *this;
+    }
+
+    template <typename D, typename... Extra>
+    class_ &def_readwrite_static(const char *name, D *pm, const Extra &...extra) {
+        cpp_function fget([pm](const object &) -> const D & { return *pm; }, scope(*this)),
+            fset([pm](const object &, const D &value) { *pm = value; }, scope(*this));
+        def_property_static(name, fget, fset, return_value_policy::reference, extra...);
+        return *this;
+    }
+
+    template <typename D, typename... Extra>
+    class_ &def_readonly_static(const char *name, const D *pm, const Extra &...extra) {
+        cpp_function fget([pm](const object &) -> const D & { return *pm; }, scope(*this));
+        def_property_readonly_static(name, fget, return_value_policy::reference, extra...);
+        return *this;
+    }
+
+    /// Uses return_value_policy::reference_internal by default
+    template <typename Getter, typename... Extra>
+    class_ &def_property_readonly(const char *name, const Getter &fget, const Extra &...extra) {
+        return def_property_readonly(name,
+                                     cpp_function(method_adaptor<type>(fget)),
+                                     return_value_policy::reference_internal,
+                                     extra...);
+    }
+
+    /// Uses cpp_function's return_value_policy by default
+    template <typename... Extra>
+    class_ &
+    def_property_readonly(const char *name, const cpp_function &fget, const Extra &...extra) {
+        return def_property(name, fget, nullptr, extra...);
+    }
+
+    /// Uses return_value_policy::reference by default
+    template <typename Getter, typename... Extra>
+    class_ &
+    def_property_readonly_static(const char *name, const Getter &fget, const Extra &...extra) {
+        return def_property_readonly_static(
+            name, cpp_function(fget), return_value_policy::reference, extra...);
+    }
+
+    /// Uses cpp_function's return_value_policy by default
+    template <typename... Extra>
+    class_ &def_property_readonly_static(const char *name,
+                                         const cpp_function &fget,
+                                         const Extra &...extra) {
+        return def_property_static(name, fget, nullptr, extra...);
+    }
+
+    /// Uses return_value_policy::reference_internal by default
+    template <typename Getter, typename Setter, typename... Extra>
+    class_ &
+    def_property(const char *name, const Getter &fget, const Setter &fset, const Extra &...extra) {
+        return def_property(name, fget, cpp_function(method_adaptor<type>(fset)), extra...);
+    }
+    template <typename Getter, typename... Extra>
+    class_ &def_property(const char *name,
+                         const Getter &fget,
+                         const cpp_function &fset,
+                         const Extra &...extra) {
+        return def_property(name,
+                            cpp_function(method_adaptor<type>(fget)),
+                            fset,
+                            return_value_policy::reference_internal,
+                            extra...);
+    }
+
+    /// Uses cpp_function's return_value_policy by default
+    template <typename... Extra>
+    class_ &def_property(const char *name,
+                         const cpp_function &fget,
+                         const cpp_function &fset,
+                         const Extra &...extra) {
+        return def_property_static(name, fget, fset, is_method(*this), extra...);
+    }
+
+    /// Uses return_value_policy::reference by default
+    template <typename Getter, typename... Extra>
+    class_ &def_property_static(const char *name,
+                                const Getter &fget,
+                                const cpp_function &fset,
+                                const Extra &...extra) {
+        return def_property_static(
+            name, cpp_function(fget), fset, return_value_policy::reference, extra...);
+    }
+
+    /// Uses cpp_function's return_value_policy by default
+    template <typename... Extra>
+    class_ &def_property_static(const char *name,
+                                const cpp_function &fget,
+                                const cpp_function &fset,
+                                const Extra &...extra) {
+        static_assert(0 == detail::constexpr_sum(std::is_base_of<arg, Extra>::value...),
+                      "Argument annotations are not allowed for properties");
+        auto rec_fget = get_function_record(fget), rec_fset = get_function_record(fset);
+        auto *rec_active = rec_fget;
+        if (rec_fget) {
+            char *doc_prev = rec_fget->doc; /* 'extra' field may include a property-specific
+                                               documentation string */
+            detail::process_attributes<Extra...>::init(extra..., rec_fget);
+            if (rec_fget->doc && rec_fget->doc != doc_prev) {
+                std::free(doc_prev);
+                rec_fget->doc = PYBIND11_COMPAT_STRDUP(rec_fget->doc);
+            }
+        }
+        if (rec_fset) {
+            char *doc_prev = rec_fset->doc;
+            detail::process_attributes<Extra...>::init(extra..., rec_fset);
+            if (rec_fset->doc && rec_fset->doc != doc_prev) {
+                std::free(doc_prev);
+                rec_fset->doc = PYBIND11_COMPAT_STRDUP(rec_fset->doc);
+            }
+            if (!rec_active) {
+                rec_active = rec_fset;
+            }
+        }
+        def_property_static_impl(name, fget, fset, rec_active);
+        return *this;
+    }
+
+private:
+    /// Initialize holder object, variant 1: object derives from enable_shared_from_this
+    template <typename T>
+    static void init_holder(detail::instance *inst,
+                            detail::value_and_holder &v_h,
+                            const holder_type * /* unused */,
+                            const std::enable_shared_from_this<T> * /* dummy */) {
+
+        auto sh = std::dynamic_pointer_cast<typename holder_type::element_type>(
+            detail::try_get_shared_from_this(v_h.value_ptr<type>()));
+        if (sh) {
+            new (std::addressof(v_h.holder<holder_type>())) holder_type(std::move(sh));
+            v_h.set_holder_constructed();
+        }
+
+        if (!v_h.holder_constructed() && inst->owned) {
+            new (std::addressof(v_h.holder<holder_type>())) holder_type(v_h.value_ptr<type>());
+            v_h.set_holder_constructed();
+        }
+    }
+
+    static void init_holder_from_existing(const detail::value_and_holder &v_h,
+                                          const holder_type *holder_ptr,
+                                          std::true_type /*is_copy_constructible*/) {
+        new (std::addressof(v_h.holder<holder_type>()))
+            holder_type(*reinterpret_cast<const holder_type *>(holder_ptr));
+    }
+
+    static void init_holder_from_existing(const detail::value_and_holder &v_h,
+                                          const holder_type *holder_ptr,
+                                          std::false_type /*is_copy_constructible*/) {
+        new (std::addressof(v_h.holder<holder_type>()))
+            holder_type(std::move(*const_cast<holder_type *>(holder_ptr)));
+    }
+
+    /// Initialize holder object, variant 2: try to construct from existing holder object, if
+    /// possible
+    static void init_holder(detail::instance *inst,
+                            detail::value_and_holder &v_h,
+                            const holder_type *holder_ptr,
+                            const void * /* dummy -- not enable_shared_from_this<T>) */) {
+        if (holder_ptr) {
+            init_holder_from_existing(v_h, holder_ptr, std::is_copy_constructible<holder_type>());
+            v_h.set_holder_constructed();
+        } else if (detail::always_construct_holder<holder_type>::value || inst->owned) {
+            new (std::addressof(v_h.holder<holder_type>())) holder_type(v_h.value_ptr<type>());
+            v_h.set_holder_constructed();
+        }
+    }
+
+    /// Performs instance initialization including constructing a holder and registering the known
+    /// instance.  Should be called as soon as the `type` value_ptr is set for an instance.  Takes
+    /// an optional pointer to an existing holder to use; if not specified and the instance is
+    /// `.owned`, a new holder will be constructed to manage the value pointer.
+    static void init_instance(detail::instance *inst, const void *holder_ptr) {
+        inst->has_alias = has_alias;
+        auto v_h = inst->get_value_and_holder(detail::get_type_info(typeid(type)));
+        if (!v_h.instance_registered()) {
+            register_instance(inst, v_h.value_ptr(), v_h.type);
+            v_h.set_instance_registered();
+        }
+        init_holder(inst, v_h, (const holder_type *) holder_ptr, v_h.value_ptr<type>());
+    }
+
+    /// Deallocates an instance; via holder, if constructed; otherwise via operator delete.
+    static void dealloc(detail::value_and_holder &v_h) {
+        // We could be deallocating because we are cleaning up after a Python exception.
+        // If so, the Python error indicator will be set. We need to clear that before
+        // running the destructor, in case the destructor code calls more Python.
+        // If we don't, the Python API will exit with an exception, and pybind11 will
+        // throw error_already_set from the C++ destructor which is forbidden and triggers
+        // std::terminate().
+        error_scope scope;
+        if (v_h.holder_constructed()) {
+            v_h.holder<holder_type>().~holder_type();
+            v_h.set_holder_constructed(false);
+        } else {
+            detail::call_operator_delete(
+                v_h.value_ptr<type>(), v_h.type->type_size, v_h.type->type_align);
+        }
+        v_h.value_ptr() = nullptr;
+    }
+
+    static detail::function_record *get_function_record(handle h) {
+        h = detail::get_function(h);
+        if (!h) {
+            return nullptr;
+        }
+
+        handle func_self = PyCFunction_GET_SELF(h.ptr());
+        if (!func_self) {
+            throw error_already_set();
+        }
+        if (!isinstance<capsule>(func_self)) {
+            return nullptr;
+        }
+        auto cap = reinterpret_borrow<capsule>(func_self);
+        if (!detail::is_function_record_capsule(cap)) {
+            return nullptr;
+        }
+        return cap.get_pointer<detail::function_record>();
+    }
+};
+
+/// Binds an existing constructor taking arguments Args...
+template <typename... Args>
+detail::initimpl::constructor<Args...> init() {
+    return {};
+}
+/// Like `init<Args...>()`, but the instance is always constructed through the alias class (even
+/// when not inheriting on the Python side).
+template <typename... Args>
+detail::initimpl::alias_constructor<Args...> init_alias() {
+    return {};
+}
+
+/// Binds a factory function as a constructor
+template <typename Func, typename Ret = detail::initimpl::factory<Func>>
+Ret init(Func &&f) {
+    return {std::forward<Func>(f)};
+}
+
+/// Dual-argument factory function: the first function is called when no alias is needed, the
+/// second when an alias is needed (i.e. due to python-side inheritance).  Arguments must be
+/// identical.
+template <typename CFunc, typename AFunc, typename Ret = detail::initimpl::factory<CFunc, AFunc>>
+Ret init(CFunc &&c, AFunc &&a) {
+    return {std::forward<CFunc>(c), std::forward<AFunc>(a)};
+}
+
+/// Binds pickling functions `__getstate__` and `__setstate__` and ensures that the type
+/// returned by `__getstate__` is the same as the argument accepted by `__setstate__`.
+template <typename GetState, typename SetState>
+detail::initimpl::pickle_factory<GetState, SetState> pickle(GetState &&g, SetState &&s) {
+    return {std::forward<GetState>(g), std::forward<SetState>(s)};
+}
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+inline str enum_name(handle arg) {
+    dict entries = arg.get_type().attr("__entries");
+    for (auto kv : entries) {
+        if (handle(kv.second[int_(0)]).equal(arg)) {
+            return pybind11::str(kv.first);
+        }
+    }
+    return "???";
+}
+
+struct enum_base {
+    enum_base(const handle &base, const handle &parent) : m_base(base), m_parent(parent) {}
+
+    PYBIND11_NOINLINE void init(bool is_arithmetic, bool is_convertible) {
+        m_base.attr("__entries") = dict();
+        auto property = handle((PyObject *) &PyProperty_Type);
+        auto static_property = handle((PyObject *) get_internals().static_property_type);
+
+        m_base.attr("__repr__") = cpp_function(
+            [](const object &arg) -> str {
+                handle type = type::handle_of(arg);
+                object type_name = type.attr("__name__");
+                return pybind11::str("<{}.{}: {}>")
+                    .format(std::move(type_name), enum_name(arg), int_(arg));
+            },
+            name("__repr__"),
+            is_method(m_base));
+
+        m_base.attr("name") = property(cpp_function(&enum_name, name("name"), is_method(m_base)));
+
+        m_base.attr("__str__") = cpp_function(
+            [](handle arg) -> str {
+                object type_name = type::handle_of(arg).attr("__name__");
+                return pybind11::str("{}.{}").format(std::move(type_name), enum_name(arg));
+            },
+            name("name"),
+            is_method(m_base));
+
+        if (options::show_enum_members_docstring()) {
+            m_base.attr("__doc__") = static_property(
+                cpp_function(
+                    [](handle arg) -> std::string {
+                        std::string docstring;
+                        dict entries = arg.attr("__entries");
+                        if (((PyTypeObject *) arg.ptr())->tp_doc) {
+                            docstring += std::string(
+                                reinterpret_cast<PyTypeObject *>(arg.ptr())->tp_doc);
+                            docstring += "\n\n";
+                        }
+                        docstring += "Members:";
+                        for (auto kv : entries) {
+                            auto key = std::string(pybind11::str(kv.first));
+                            auto comment = kv.second[int_(1)];
+                            docstring += "\n\n  ";
+                            docstring += key;
+                            if (!comment.is_none()) {
+                                docstring += " : ";
+                                docstring += pybind11::str(comment).cast<std::string>();
+                            }
+                        }
+                        return docstring;
+                    },
+                    name("__doc__")),
+                none(),
+                none(),
+                "");
+        }
+
+        m_base.attr("__members__") = static_property(cpp_function(
+                                                         [](handle arg) -> dict {
+                                                             dict entries = arg.attr("__entries"),
+                                                                  m;
+                                                             for (auto kv : entries) {
+                                                                 m[kv.first] = kv.second[int_(0)];
+                                                             }
+                                                             return m;
+                                                         },
+                                                         name("__members__")),
+                                                     none(),
+                                                     none(),
+                                                     "");
+
+#define PYBIND11_ENUM_OP_STRICT(op, expr, strict_behavior)                                        \
+    m_base.attr(op) = cpp_function(                                                               \
+        [](const object &a, const object &b) {                                                    \
+            if (!type::handle_of(a).is(type::handle_of(b)))                                       \
+                strict_behavior; /* NOLINT(bugprone-macro-parentheses) */                         \
+            return expr;                                                                          \
+        },                                                                                        \
+        name(op),                                                                                 \
+        is_method(m_base),                                                                        \
+        arg("other"))
+
+#define PYBIND11_ENUM_OP_CONV(op, expr)                                                           \
+    m_base.attr(op) = cpp_function(                                                               \
+        [](const object &a_, const object &b_) {                                                  \
+            int_ a(a_), b(b_);                                                                    \
+            return expr;                                                                          \
+        },                                                                                        \
+        name(op),                                                                                 \
+        is_method(m_base),                                                                        \
+        arg("other"))
+
+#define PYBIND11_ENUM_OP_CONV_LHS(op, expr)                                                       \
+    m_base.attr(op) = cpp_function(                                                               \
+        [](const object &a_, const object &b) {                                                   \
+            int_ a(a_);                                                                           \
+            return expr;                                                                          \
+        },                                                                                        \
+        name(op),                                                                                 \
+        is_method(m_base),                                                                        \
+        arg("other"))
+
+        if (is_convertible) {
+            PYBIND11_ENUM_OP_CONV_LHS("__eq__", !b.is_none() && a.equal(b));
+            PYBIND11_ENUM_OP_CONV_LHS("__ne__", b.is_none() || !a.equal(b));
+
+            if (is_arithmetic) {
+                PYBIND11_ENUM_OP_CONV("__lt__", a < b);
+                PYBIND11_ENUM_OP_CONV("__gt__", a > b);
+                PYBIND11_ENUM_OP_CONV("__le__", a <= b);
+                PYBIND11_ENUM_OP_CONV("__ge__", a >= b);
+                PYBIND11_ENUM_OP_CONV("__and__", a & b);
+                PYBIND11_ENUM_OP_CONV("__rand__", a & b);
+                PYBIND11_ENUM_OP_CONV("__or__", a | b);
+                PYBIND11_ENUM_OP_CONV("__ror__", a | b);
+                PYBIND11_ENUM_OP_CONV("__xor__", a ^ b);
+                PYBIND11_ENUM_OP_CONV("__rxor__", a ^ b);
+                m_base.attr("__invert__")
+                    = cpp_function([](const object &arg) { return ~(int_(arg)); },
+                                   name("__invert__"),
+                                   is_method(m_base));
+            }
+        } else {
+            PYBIND11_ENUM_OP_STRICT("__eq__", int_(a).equal(int_(b)), return false);
+            PYBIND11_ENUM_OP_STRICT("__ne__", !int_(a).equal(int_(b)), return true);
+
+            if (is_arithmetic) {
+#define PYBIND11_THROW throw type_error("Expected an enumeration of matching type!");
+                PYBIND11_ENUM_OP_STRICT("__lt__", int_(a) < int_(b), PYBIND11_THROW);
+                PYBIND11_ENUM_OP_STRICT("__gt__", int_(a) > int_(b), PYBIND11_THROW);
+                PYBIND11_ENUM_OP_STRICT("__le__", int_(a) <= int_(b), PYBIND11_THROW);
+                PYBIND11_ENUM_OP_STRICT("__ge__", int_(a) >= int_(b), PYBIND11_THROW);
+#undef PYBIND11_THROW
+            }
+        }
+
+#undef PYBIND11_ENUM_OP_CONV_LHS
+#undef PYBIND11_ENUM_OP_CONV
+#undef PYBIND11_ENUM_OP_STRICT
+
+        m_base.attr("__getstate__") = cpp_function(
+            [](const object &arg) { return int_(arg); }, name("__getstate__"), is_method(m_base));
+
+        m_base.attr("__hash__") = cpp_function(
+            [](const object &arg) { return int_(arg); }, name("__hash__"), is_method(m_base));
+    }
+
+    PYBIND11_NOINLINE void value(char const *name_, object value, const char *doc = nullptr) {
+        dict entries = m_base.attr("__entries");
+        str name(name_);
+        if (entries.contains(name)) {
+            std::string type_name = (std::string) str(m_base.attr("__name__"));
+            throw value_error(std::move(type_name) + ": element \"" + std::string(name_)
+                              + "\" already exists!");
+        }
+
+        entries[name] = pybind11::make_tuple(value, doc);
+        m_base.attr(std::move(name)) = std::move(value);
+    }
+
+    PYBIND11_NOINLINE void export_values() {
+        dict entries = m_base.attr("__entries");
+        for (auto kv : entries) {
+            m_parent.attr(kv.first) = kv.second[int_(0)];
+        }
+    }
+
+    handle m_base;
+    handle m_parent;
+};
+
+template <bool is_signed, size_t length>
+struct equivalent_integer {};
+template <>
+struct equivalent_integer<true, 1> {
+    using type = int8_t;
+};
+template <>
+struct equivalent_integer<false, 1> {
+    using type = uint8_t;
+};
+template <>
+struct equivalent_integer<true, 2> {
+    using type = int16_t;
+};
+template <>
+struct equivalent_integer<false, 2> {
+    using type = uint16_t;
+};
+template <>
+struct equivalent_integer<true, 4> {
+    using type = int32_t;
+};
+template <>
+struct equivalent_integer<false, 4> {
+    using type = uint32_t;
+};
+template <>
+struct equivalent_integer<true, 8> {
+    using type = int64_t;
+};
+template <>
+struct equivalent_integer<false, 8> {
+    using type = uint64_t;
+};
+
+template <typename IntLike>
+using equivalent_integer_t =
+    typename equivalent_integer<std::is_signed<IntLike>::value, sizeof(IntLike)>::type;
+
+PYBIND11_NAMESPACE_END(detail)
+
+/// Binds C++ enumerations and enumeration classes to Python
+template <typename Type>
+class enum_ : public class_<Type> {
+public:
+    using Base = class_<Type>;
+    using Base::attr;
+    using Base::def;
+    using Base::def_property_readonly;
+    using Base::def_property_readonly_static;
+    using Underlying = typename std::underlying_type<Type>::type;
+    // Scalar is the integer representation of underlying type
+    using Scalar = detail::conditional_t<detail::any_of<detail::is_std_char_type<Underlying>,
+                                                        std::is_same<Underlying, bool>>::value,
+                                         detail::equivalent_integer_t<Underlying>,
+                                         Underlying>;
+
+    template <typename... Extra>
+    enum_(const handle &scope, const char *name, const Extra &...extra)
+        : class_<Type>(scope, name, extra...), m_base(*this, scope) {
+        constexpr bool is_arithmetic = detail::any_of<std::is_same<arithmetic, Extra>...>::value;
+        constexpr bool is_convertible = std::is_convertible<Type, Underlying>::value;
+        m_base.init(is_arithmetic, is_convertible);
+
+        def(init([](Scalar i) { return static_cast<Type>(i); }), arg("value"));
+        def_property_readonly("value", [](Type value) { return (Scalar) value; });
+        def("__int__", [](Type value) { return (Scalar) value; });
+        def("__index__", [](Type value) { return (Scalar) value; });
+        attr("__setstate__") = cpp_function(
+            [](detail::value_and_holder &v_h, Scalar arg) {
+                detail::initimpl::setstate<Base>(
+                    v_h, static_cast<Type>(arg), Py_TYPE(v_h.inst) != v_h.type->type);
+            },
+            detail::is_new_style_constructor(),
+            pybind11::name("__setstate__"),
+            is_method(*this),
+            arg("state"));
+    }
+
+    /// Export enumeration entries into the parent scope
+    enum_ &export_values() {
+        m_base.export_values();
+        return *this;
+    }
+
+    /// Add an enumeration entry
+    enum_ &value(char const *name, Type value, const char *doc = nullptr) {
+        m_base.value(name, pybind11::cast(value, return_value_policy::copy), doc);
+        return *this;
+    }
+
+private:
+    detail::enum_base m_base;
+};
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+PYBIND11_NOINLINE void keep_alive_impl(handle nurse, handle patient) {
+    if (!nurse || !patient) {
+        pybind11_fail("Could not activate keep_alive!");
+    }
+
+    if (patient.is_none() || nurse.is_none()) {
+        return; /* Nothing to keep alive or nothing to be kept alive by */
+    }
+
+    auto tinfo = all_type_info(Py_TYPE(nurse.ptr()));
+    if (!tinfo.empty()) {
+        /* It's a pybind-registered type, so we can store the patient in the
+         * internal list. */
+        add_patient(nurse.ptr(), patient.ptr());
+    } else {
+        /* Fall back to clever approach based on weak references taken from
+         * Boost.Python. This is not used for pybind-registered types because
+         * the objects can be destroyed out-of-order in a GC pass. */
+        cpp_function disable_lifesupport([patient](handle weakref) {
+            patient.dec_ref();
+            weakref.dec_ref();
+        });
+
+        weakref wr(nurse, disable_lifesupport);
+
+        patient.inc_ref(); /* reference patient and leak the weak reference */
+        (void) wr.release();
+    }
+}
+
+PYBIND11_NOINLINE void
+keep_alive_impl(size_t Nurse, size_t Patient, function_call &call, handle ret) {
+    auto get_arg = [&](size_t n) {
+        if (n == 0) {
+            return ret;
+        }
+        if (n == 1 && call.init_self) {
+            return call.init_self;
+        }
+        if (n <= call.args.size()) {
+            return call.args[n - 1];
+        }
+        return handle();
+    };
+
+    keep_alive_impl(get_arg(Nurse), get_arg(Patient));
+}
+
+inline std::pair<decltype(internals::registered_types_py)::iterator, bool>
+all_type_info_get_cache(PyTypeObject *type) {
+    auto res = get_internals()
+                   .registered_types_py
+#ifdef __cpp_lib_unordered_map_try_emplace
+                   .try_emplace(type);
+#else
+                   .emplace(type, std::vector<detail::type_info *>());
+#endif
+    if (res.second) {
+        // New cache entry created; set up a weak reference to automatically remove it if the type
+        // gets destroyed:
+        weakref((PyObject *) type, cpp_function([type](handle wr) {
+                    get_internals().registered_types_py.erase(type);
+
+                    // TODO consolidate the erasure code in pybind11_meta_dealloc() in class.h
+                    auto &cache = get_internals().inactive_override_cache;
+                    for (auto it = cache.begin(), last = cache.end(); it != last;) {
+                        if (it->first == reinterpret_cast<PyObject *>(type)) {
+                            it = cache.erase(it);
+                        } else {
+                            ++it;
+                        }
+                    }
+
+                    wr.dec_ref();
+                }))
+            .release();
+    }
+
+    return res;
+}
+
+/* There are a large number of apparently unused template arguments because
+ * each combination requires a separate py::class_ registration.
+ */
+template <typename Access,
+          return_value_policy Policy,
+          typename Iterator,
+          typename Sentinel,
+          typename ValueType,
+          typename... Extra>
+struct iterator_state {
+    Iterator it;
+    Sentinel end;
+    bool first_or_done;
+};
+
+// Note: these helpers take the iterator by non-const reference because some
+// iterators in the wild can't be dereferenced when const. The & after Iterator
+// is required for MSVC < 16.9. SFINAE cannot be reused for result_type due to
+// bugs in ICC, NVCC, and PGI compilers. See PR #3293.
+template <typename Iterator, typename SFINAE = decltype(*std::declval<Iterator &>())>
+struct iterator_access {
+    using result_type = decltype(*std::declval<Iterator &>());
+    // NOLINTNEXTLINE(readability-const-return-type) // PR #3263
+    result_type operator()(Iterator &it) const { return *it; }
+};
+
+template <typename Iterator, typename SFINAE = decltype((*std::declval<Iterator &>()).first)>
+class iterator_key_access {
+private:
+    using pair_type = decltype(*std::declval<Iterator &>());
+
+public:
+    /* If either the pair itself or the element of the pair is a reference, we
+     * want to return a reference, otherwise a value. When the decltype
+     * expression is parenthesized it is based on the value category of the
+     * expression; otherwise it is the declared type of the pair member.
+     * The use of declval<pair_type> in the second branch rather than directly
+     * using *std::declval<Iterator &>() is a workaround for nvcc
+     * (it's not used in the first branch because going via decltype and back
+     * through declval does not perfectly preserve references).
+     */
+    using result_type
+        = conditional_t<std::is_reference<decltype(*std::declval<Iterator &>())>::value,
+                        decltype(((*std::declval<Iterator &>()).first)),
+                        decltype(std::declval<pair_type>().first)>;
+    result_type operator()(Iterator &it) const { return (*it).first; }
+};
+
+template <typename Iterator, typename SFINAE = decltype((*std::declval<Iterator &>()).second)>
+class iterator_value_access {
+private:
+    using pair_type = decltype(*std::declval<Iterator &>());
+
+public:
+    using result_type
+        = conditional_t<std::is_reference<decltype(*std::declval<Iterator &>())>::value,
+                        decltype(((*std::declval<Iterator &>()).second)),
+                        decltype(std::declval<pair_type>().second)>;
+    result_type operator()(Iterator &it) const { return (*it).second; }
+};
+
+template <typename Access,
+          return_value_policy Policy,
+          typename Iterator,
+          typename Sentinel,
+          typename ValueType,
+          typename... Extra>
+iterator make_iterator_impl(Iterator first, Sentinel last, Extra &&...extra) {
+    using state = detail::iterator_state<Access, Policy, Iterator, Sentinel, ValueType, Extra...>;
+    // TODO: state captures only the types of Extra, not the values
+
+    if (!detail::get_type_info(typeid(state), false)) {
+        class_<state>(handle(), "iterator", pybind11::module_local())
+            .def("__iter__", [](state &s) -> state & { return s; })
+            .def(
+                "__next__",
+                [](state &s) -> ValueType {
+                    if (!s.first_or_done) {
+                        ++s.it;
+                    } else {
+                        s.first_or_done = false;
+                    }
+                    if (s.it == s.end) {
+                        s.first_or_done = true;
+                        throw stop_iteration();
+                    }
+                    return Access()(s.it);
+                    // NOLINTNEXTLINE(readability-const-return-type) // PR #3263
+                },
+                std::forward<Extra>(extra)...,
+                Policy);
+    }
+
+    return cast(state{first, last, true});
+}
+
+PYBIND11_NAMESPACE_END(detail)
+
+/// Makes a python iterator from a first and past-the-end C++ InputIterator.
+template <return_value_policy Policy = return_value_policy::reference_internal,
+          typename Iterator,
+          typename Sentinel,
+          typename ValueType = typename detail::iterator_access<Iterator>::result_type,
+          typename... Extra>
+iterator make_iterator(Iterator first, Sentinel last, Extra &&...extra) {
+    return detail::make_iterator_impl<detail::iterator_access<Iterator>,
+                                      Policy,
+                                      Iterator,
+                                      Sentinel,
+                                      ValueType,
+                                      Extra...>(first, last, std::forward<Extra>(extra)...);
+}
+
+/// Makes a python iterator over the keys (`.first`) of a iterator over pairs from a
+/// first and past-the-end InputIterator.
+template <return_value_policy Policy = return_value_policy::reference_internal,
+          typename Iterator,
+          typename Sentinel,
+          typename KeyType = typename detail::iterator_key_access<Iterator>::result_type,
+          typename... Extra>
+iterator make_key_iterator(Iterator first, Sentinel last, Extra &&...extra) {
+    return detail::make_iterator_impl<detail::iterator_key_access<Iterator>,
+                                      Policy,
+                                      Iterator,
+                                      Sentinel,
+                                      KeyType,
+                                      Extra...>(first, last, std::forward<Extra>(extra)...);
+}
+
+/// Makes a python iterator over the values (`.second`) of a iterator over pairs from a
+/// first and past-the-end InputIterator.
+template <return_value_policy Policy = return_value_policy::reference_internal,
+          typename Iterator,
+          typename Sentinel,
+          typename ValueType = typename detail::iterator_value_access<Iterator>::result_type,
+          typename... Extra>
+iterator make_value_iterator(Iterator first, Sentinel last, Extra &&...extra) {
+    return detail::make_iterator_impl<detail::iterator_value_access<Iterator>,
+                                      Policy,
+                                      Iterator,
+                                      Sentinel,
+                                      ValueType,
+                                      Extra...>(first, last, std::forward<Extra>(extra)...);
+}
+
+/// Makes an iterator over values of an stl container or other container supporting
+/// `std::begin()`/`std::end()`
+template <return_value_policy Policy = return_value_policy::reference_internal,
+          typename Type,
+          typename... Extra>
+iterator make_iterator(Type &value, Extra &&...extra) {
+    return make_iterator<Policy>(
+        std::begin(value), std::end(value), std::forward<Extra>(extra)...);
+}
+
+/// Makes an iterator over the keys (`.first`) of a stl map-like container supporting
+/// `std::begin()`/`std::end()`
+template <return_value_policy Policy = return_value_policy::reference_internal,
+          typename Type,
+          typename... Extra>
+iterator make_key_iterator(Type &value, Extra &&...extra) {
+    return make_key_iterator<Policy>(
+        std::begin(value), std::end(value), std::forward<Extra>(extra)...);
+}
+
+/// Makes an iterator over the values (`.second`) of a stl map-like container supporting
+/// `std::begin()`/`std::end()`
+template <return_value_policy Policy = return_value_policy::reference_internal,
+          typename Type,
+          typename... Extra>
+iterator make_value_iterator(Type &value, Extra &&...extra) {
+    return make_value_iterator<Policy>(
+        std::begin(value), std::end(value), std::forward<Extra>(extra)...);
+}
+
+template <typename InputType, typename OutputType>
+void implicitly_convertible() {
+    struct set_flag {
+        bool &flag;
+        explicit set_flag(bool &flag_) : flag(flag_) { flag_ = true; }
+        ~set_flag() { flag = false; }
+    };
+    auto implicit_caster = [](PyObject *obj, PyTypeObject *type) -> PyObject * {
+        static bool currently_used = false;
+        if (currently_used) { // implicit conversions are non-reentrant
+            return nullptr;
+        }
+        set_flag flag_helper(currently_used);
+        if (!detail::make_caster<InputType>().load(obj, false)) {
+            return nullptr;
+        }
+        tuple args(1);
+        args[0] = obj;
+        PyObject *result = PyObject_Call((PyObject *) type, args.ptr(), nullptr);
+        if (result == nullptr) {
+            PyErr_Clear();
+        }
+        return result;
+    };
+
+    if (auto *tinfo = detail::get_type_info(typeid(OutputType))) {
+        tinfo->implicit_conversions.emplace_back(std::move(implicit_caster));
+    } else {
+        pybind11_fail("implicitly_convertible: Unable to find type " + type_id<OutputType>());
+    }
+}
+
+inline void register_exception_translator(ExceptionTranslator &&translator) {
+    detail::get_internals().registered_exception_translators.push_front(
+        std::forward<ExceptionTranslator>(translator));
+}
+
+/**
+ * Add a new module-local exception translator. Locally registered functions
+ * will be tried before any globally registered exception translators, which
+ * will only be invoked if the module-local handlers do not deal with
+ * the exception.
+ */
+inline void register_local_exception_translator(ExceptionTranslator &&translator) {
+    detail::get_local_internals().registered_exception_translators.push_front(
+        std::forward<ExceptionTranslator>(translator));
+}
+
+/**
+ * Wrapper to generate a new Python exception type.
+ *
+ * This should only be used with PyErr_SetString for now.
+ * It is not (yet) possible to use as a py::base.
+ * Template type argument is reserved for future use.
+ */
+template <typename type>
+class exception : public object {
+public:
+    exception() = default;
+    exception(handle scope, const char *name, handle base = PyExc_Exception) {
+        std::string full_name
+            = scope.attr("__name__").cast<std::string>() + std::string(".") + name;
+        m_ptr = PyErr_NewException(const_cast<char *>(full_name.c_str()), base.ptr(), nullptr);
+        if (hasattr(scope, "__dict__") && scope.attr("__dict__").contains(name)) {
+            pybind11_fail("Error during initialization: multiple incompatible "
+                          "definitions with name \""
+                          + std::string(name) + "\"");
+        }
+        scope.attr(name) = *this;
+    }
+
+    // Sets the current python exception to this exception object with the given message
+    void operator()(const char *message) { PyErr_SetString(m_ptr, message); }
+};
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+// Returns a reference to a function-local static exception object used in the simple
+// register_exception approach below.  (It would be simpler to have the static local variable
+// directly in register_exception, but that makes clang <3.5 segfault - issue #1349).
+template <typename CppException>
+exception<CppException> &get_exception_object() {
+    static exception<CppException> ex;
+    return ex;
+}
+
+// Helper function for register_exception and register_local_exception
+template <typename CppException>
+exception<CppException> &
+register_exception_impl(handle scope, const char *name, handle base, bool isLocal) {
+    auto &ex = detail::get_exception_object<CppException>();
+    if (!ex) {
+        ex = exception<CppException>(scope, name, base);
+    }
+
+    auto register_func
+        = isLocal ? &register_local_exception_translator : &register_exception_translator;
+
+    register_func([](std::exception_ptr p) {
+        if (!p) {
+            return;
+        }
+        try {
+            std::rethrow_exception(p);
+        } catch (const CppException &e) {
+            detail::get_exception_object<CppException>()(e.what());
+        }
+    });
+    return ex;
+}
+
+PYBIND11_NAMESPACE_END(detail)
+
+/**
+ * Registers a Python exception in `m` of the given `name` and installs a translator to
+ * translate the C++ exception to the created Python exception using the what() method.
+ * This is intended for simple exception translations; for more complex translation, register the
+ * exception object and translator directly.
+ */
+template <typename CppException>
+exception<CppException> &
+register_exception(handle scope, const char *name, handle base = PyExc_Exception) {
+    return detail::register_exception_impl<CppException>(scope, name, base, false /* isLocal */);
+}
+
+/**
+ * Registers a Python exception in `m` of the given `name` and installs a translator to
+ * translate the C++ exception to the created Python exception using the what() method.
+ * This translator will only be used for exceptions that are thrown in this module and will be
+ * tried before global exception translators, including those registered with register_exception.
+ * This is intended for simple exception translations; for more complex translation, register the
+ * exception object and translator directly.
+ */
+template <typename CppException>
+exception<CppException> &
+register_local_exception(handle scope, const char *name, handle base = PyExc_Exception) {
+    return detail::register_exception_impl<CppException>(scope, name, base, true /* isLocal */);
+}
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+PYBIND11_NOINLINE void print(const tuple &args, const dict &kwargs) {
+    auto strings = tuple(args.size());
+    for (size_t i = 0; i < args.size(); ++i) {
+        strings[i] = str(args[i]);
+    }
+    auto sep = kwargs.contains("sep") ? kwargs["sep"] : str(" ");
+    auto line = sep.attr("join")(std::move(strings));
+
+    object file;
+    if (kwargs.contains("file")) {
+        file = kwargs["file"].cast<object>();
+    } else {
+        try {
+            file = module_::import("sys").attr("stdout");
+        } catch (const error_already_set &) {
+            /* If print() is called from code that is executed as
+               part of garbage collection during interpreter shutdown,
+               importing 'sys' can fail. Give up rather than crashing the
+               interpreter in this case. */
+            return;
+        }
+    }
+
+    auto write = file.attr("write");
+    write(std::move(line));
+    write(kwargs.contains("end") ? kwargs["end"] : str("\n"));
+
+    if (kwargs.contains("flush") && kwargs["flush"].cast<bool>()) {
+        file.attr("flush")();
+    }
+}
+PYBIND11_NAMESPACE_END(detail)
+
+template <return_value_policy policy = return_value_policy::automatic_reference, typename... Args>
+void print(Args &&...args) {
+    auto c = detail::collect_arguments<policy>(std::forward<Args>(args)...);
+    detail::print(c.args(), c.kwargs());
+}
+
+inline void
+error_already_set::m_fetched_error_deleter(detail::error_fetch_and_normalize *raw_ptr) {
+    gil_scoped_acquire gil;
+    error_scope scope;
+    delete raw_ptr;
+}
+
+inline const char *error_already_set::what() const noexcept {
+    gil_scoped_acquire gil;
+    error_scope scope;
+    return m_fetched_error->error_string().c_str();
+}
+
+PYBIND11_NAMESPACE_BEGIN(detail)
+
+inline function
+get_type_override(const void *this_ptr, const type_info *this_type, const char *name) {
+    handle self = get_object_handle(this_ptr, this_type);
+    if (!self) {
+        return function();
+    }
+    handle type = type::handle_of(self);
+    auto key = std::make_pair(type.ptr(), name);
+
+    /* Cache functions that aren't overridden in Python to avoid
+       many costly Python dictionary lookups below */
+    auto &cache = get_internals().inactive_override_cache;
+    if (cache.find(key) != cache.end()) {
+        return function();
+    }
+
+    function override = getattr(self, name, function());
+    if (override.is_cpp_function()) {
+        cache.insert(std::move(key));
+        return function();
+    }
+
+    /* Don't call dispatch code if invoked from overridden function.
+       Unfortunately this doesn't work on PyPy. */
+#if !defined(PYPY_VERSION)
+#    if PY_VERSION_HEX >= 0x03090000
+    PyFrameObject *frame = PyThreadState_GetFrame(PyThreadState_Get());
+    if (frame != nullptr) {
+        PyCodeObject *f_code = PyFrame_GetCode(frame);
+        // f_code is guaranteed to not be NULL
+        if ((std::string) str(f_code->co_name) == name && f_code->co_argcount > 0) {
+            PyObject *locals = PyEval_GetLocals();
+            if (locals != nullptr) {
+                PyObject *co_varnames = PyObject_GetAttrString((PyObject *) f_code, "co_varnames");
+                PyObject *self_arg = PyTuple_GET_ITEM(co_varnames, 0);
+                Py_DECREF(co_varnames);
+                PyObject *self_caller = dict_getitem(locals, self_arg);
+                if (self_caller == self.ptr()) {
+                    Py_DECREF(f_code);
+                    Py_DECREF(frame);
+                    return function();
+                }
+            }
+        }
+        Py_DECREF(f_code);
+        Py_DECREF(frame);
+    }
+#    else
+    PyFrameObject *frame = PyThreadState_Get()->frame;
+    if (frame != nullptr && (std::string) str(frame->f_code->co_name) == name
+        && frame->f_code->co_argcount > 0) {
+        PyFrame_FastToLocals(frame);
+        PyObject *self_caller
+            = dict_getitem(frame->f_locals, PyTuple_GET_ITEM(frame->f_code->co_varnames, 0));
+        if (self_caller == self.ptr()) {
+            return function();
+        }
+    }
+#    endif
+
+#else
+    /* PyPy currently doesn't provide a detailed cpyext emulation of
+       frame objects, so we have to emulate this using Python. This
+       is going to be slow..*/
+    dict d;
+    d["self"] = self;
+    d["name"] = pybind11::str(name);
+    PyObject *result
+        = PyRun_String("import inspect\n"
+                       "frame = inspect.currentframe()\n"
+                       "if frame is not None:\n"
+                       "    frame = frame.f_back\n"
+                       "    if frame is not None and str(frame.f_code.co_name) == name and "
+                       "frame.f_code.co_argcount > 0:\n"
+                       "        self_caller = frame.f_locals[frame.f_code.co_varnames[0]]\n"
+                       "        if self_caller == self:\n"
+                       "            self = None\n",
+                       Py_file_input,
+                       d.ptr(),
+                       d.ptr());
+    if (result == nullptr)
+        throw error_already_set();
+    Py_DECREF(result);
+    if (d["self"].is_none())
+        return function();
+#endif
+
+    return override;
+}
+PYBIND11_NAMESPACE_END(detail)
+
+/** \rst
+  Try to retrieve a python method by the provided name from the instance pointed to by the
+  this_ptr.
+
+  :this_ptr: The pointer to the object the overridden method should be retrieved for. This should
+             be the first non-trampoline class encountered in the inheritance chain.
+  :name: The name of the overridden Python method to retrieve.
+  :return: The Python method by this name from the object or an empty function wrapper.
+ \endrst */
+template <class T>
+function get_override(const T *this_ptr, const char *name) {
+    auto *tinfo = detail::get_type_info(typeid(T));
+    return tinfo ? detail::get_type_override(this_ptr, tinfo, name) : function();
+}
+
+#define PYBIND11_OVERRIDE_IMPL(ret_type, cname, name, ...)                                        \
+    do {                                                                                          \
+        pybind11::gil_scoped_acquire gil;                                                         \
+        pybind11::function override                                                               \
+            = pybind11::get_override(static_cast<const cname *>(this), name);                     \
+        if (override) {                                                                           \
+            auto o = override(__VA_ARGS__);                                                       \
+            if (pybind11::detail::cast_is_temporary_value_reference<ret_type>::value) {           \
+                static pybind11::detail::override_caster_t<ret_type> caster;                      \
+                return pybind11::detail::cast_ref<ret_type>(std::move(o), caster);                \
+            }                                                                                     \
+            return pybind11::detail::cast_safe<ret_type>(std::move(o));                           \
+        }                                                                                         \
+    } while (false)
+
+/** \rst
+    Macro to populate the virtual method in the trampoline class. This macro tries to look up a
+    method named 'fn' from the Python side, deals with the :ref:`gil` and necessary argument
+    conversions to call this method and return the appropriate type.
+    See :ref:`overriding_virtuals` for more information. This macro should be used when the method
+    name in C is not the same as the method name in Python. For example with `__str__`.
+
+    .. code-block:: cpp
+
+      std::string toString() override {
+        PYBIND11_OVERRIDE_NAME(
+            std::string, // Return type (ret_type)
+            Animal,      // Parent class (cname)
+            "__str__",   // Name of method in Python (name)
+            toString,    // Name of function in C++ (fn)
+        );
+      }
+\endrst */
+#define PYBIND11_OVERRIDE_NAME(ret_type, cname, name, fn, ...)                                    \
+    do {                                                                                          \
+        PYBIND11_OVERRIDE_IMPL(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), name, __VA_ARGS__); \
+        return cname::fn(__VA_ARGS__);                                                            \
+    } while (false)
+
+/** \rst
+    Macro for pure virtual functions, this function is identical to
+    :c:macro:`PYBIND11_OVERRIDE_NAME`, except that it throws if no override can be found.
+\endrst */
+#define PYBIND11_OVERRIDE_PURE_NAME(ret_type, cname, name, fn, ...)                               \
+    do {                                                                                          \
+        PYBIND11_OVERRIDE_IMPL(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), name, __VA_ARGS__); \
+        pybind11::pybind11_fail(                                                                  \
+            "Tried to call pure virtual function \"" PYBIND11_STRINGIFY(cname) "::" name "\"");   \
+    } while (false)
+
+/** \rst
+    Macro to populate the virtual method in the trampoline class. This macro tries to look up the
+    method from the Python side, deals with the :ref:`gil` and necessary argument conversions to
+    call this method and return the appropriate type. This macro should be used if the method name
+    in C and in Python are identical.
+    See :ref:`overriding_virtuals` for more information.
+
+    .. code-block:: cpp
+
+      class PyAnimal : public Animal {
+      public:
+          // Inherit the constructors
+          using Animal::Animal;
+
+          // Trampoline (need one for each virtual function)
+          std::string go(int n_times) override {
+              PYBIND11_OVERRIDE_PURE(
+                  std::string, // Return type (ret_type)
+                  Animal,      // Parent class (cname)
+                  go,          // Name of function in C++ (must match Python name) (fn)
+                  n_times      // Argument(s) (...)
+              );
+          }
+      };
+\endrst */
+#define PYBIND11_OVERRIDE(ret_type, cname, fn, ...)                                               \
+    PYBIND11_OVERRIDE_NAME(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), #fn, fn, __VA_ARGS__)
+
+/** \rst
+    Macro for pure virtual functions, this function is identical to :c:macro:`PYBIND11_OVERRIDE`,
+    except that it throws if no override can be found.
+\endrst */
+#define PYBIND11_OVERRIDE_PURE(ret_type, cname, fn, ...)                                          \
+    PYBIND11_OVERRIDE_PURE_NAME(                                                                  \
+        PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), #fn, fn, __VA_ARGS__)
+
+// Deprecated versions
+
+PYBIND11_DEPRECATED("get_type_overload has been deprecated")
+inline function
+get_type_overload(const void *this_ptr, const detail::type_info *this_type, const char *name) {
+    return detail::get_type_override(this_ptr, this_type, name);
+}
+
+template <class T>
+inline function get_overload(const T *this_ptr, const char *name) {
+    return get_override(this_ptr, name);
+}
+
+#define PYBIND11_OVERLOAD_INT(ret_type, cname, name, ...)                                         \
+    PYBIND11_OVERRIDE_IMPL(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), name, __VA_ARGS__)
+#define PYBIND11_OVERLOAD_NAME(ret_type, cname, name, fn, ...)                                    \
+    PYBIND11_OVERRIDE_NAME(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), name, fn, __VA_ARGS__)
+#define PYBIND11_OVERLOAD_PURE_NAME(ret_type, cname, name, fn, ...)                               \
+    PYBIND11_OVERRIDE_PURE_NAME(                                                                  \
+        PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), name, fn, __VA_ARGS__);
+#define PYBIND11_OVERLOAD(ret_type, cname, fn, ...)                                               \
+    PYBIND11_OVERRIDE(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), fn, __VA_ARGS__)
+#define PYBIND11_OVERLOAD_PURE(ret_type, cname, fn, ...)                                          \
+    PYBIND11_OVERRIDE_PURE(PYBIND11_TYPE(ret_type), PYBIND11_TYPE(cname), fn, __VA_ARGS__);
+
+PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)