diff --git a/Makefile.toml b/Makefile.toml
index e11428955..bb5921059 100644
--- a/Makefile.toml
+++ b/Makefile.toml
@@ -202,6 +202,7 @@ exec --fail-on-error npm run test
 [tasks.test-dart-example]
 category = "Tests"
 script_runner = "@duckscript"
+dependencies = ["build-example"]
 script = '''
 exit_on_error true
 cd example/dart/
@@ -212,6 +213,7 @@ exec --fail-on-error dart --enable-experiment=native-assets test
 [tasks.test-dart-feature]
 category = "Tests"
 script_runner = "@duckscript"
+dependencies = ["build-feature"]
 script = '''
 exit_on_error true
 cd feature_tests/dart/
diff --git a/core/src/ast/attrs.rs b/core/src/ast/attrs.rs
index 7be6704e2..fb4a0504c 100644
--- a/core/src/ast/attrs.rs
+++ b/core/src/ast/attrs.rs
@@ -11,13 +11,19 @@ use syn::{Attribute, Ident, LitStr, Meta, Token};
 pub struct Attrs {
     pub cfg: Vec<Attribute>,
     pub attrs: Vec<DiplomatBackendAttr>,
+    /// AST backends only. For using features that may panic AST backends, like returning references.
+    ///
+    /// This isn't a regular attribute since AST backends do not handle regular attributes. Do not use
+    /// in HIR backends,
+    pub skip_if_unsupported: bool,
 }
 
 impl Attrs {
     fn add_attr(&mut self, attr: Attr) {
         match attr {
             Attr::Cfg(attr) => self.cfg.push(attr),
-            Attr::DiplomatBackendAttr(attr) => self.attrs.push(attr),
+            Attr::DiplomatBackend(attr) => self.attrs.push(attr),
+            Attr::SkipIfUnsupported => self.skip_if_unsupported = true,
         }
     }
 
@@ -45,21 +51,25 @@ impl From<&[Attribute]> for Attrs {
 
 enum Attr {
     Cfg(Attribute),
-    DiplomatBackendAttr(DiplomatBackendAttr),
+    DiplomatBackend(DiplomatBackendAttr),
+    SkipIfUnsupported,
     // More goes here
 }
 
 fn syn_attr_to_ast_attr(attrs: &[Attribute]) -> impl Iterator<Item = Attr> + '_ {
     let cfg_path: syn::Path = syn::parse_str("cfg").unwrap();
     let dattr_path: syn::Path = syn::parse_str("diplomat::attr").unwrap();
+    let skipast: syn::Path = syn::parse_str("diplomat::skip_if_unsupported").unwrap();
     attrs.iter().filter_map(move |a| {
         if a.path() == &cfg_path {
             Some(Attr::Cfg(a.clone()))
         } else if a.path() == &dattr_path {
-            Some(Attr::DiplomatBackendAttr(
+            Some(Attr::DiplomatBackend(
                 a.parse_args()
                     .expect("Failed to parse malformed diplomat::attr"),
             ))
+        } else if a.path() == &skipast {
+            Some(Attr::SkipIfUnsupported)
         } else {
             None
         }
diff --git a/example/dart/lib/src/ICU4XDataProvider.g.dart b/example/dart/lib/src/ICU4XDataProvider.g.dart
index 3bf3a4360..09f1b5812 100644
--- a/example/dart/lib/src/ICU4XDataProvider.g.dart
+++ b/example/dart/lib/src/ICU4XDataProvider.g.dart
@@ -11,8 +11,10 @@ part of 'lib.g.dart';
 final class ICU4XDataProvider implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  ICU4XDataProvider._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  ICU4XDataProvider._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_ICU4XDataProvider_destroy));
@@ -20,7 +22,7 @@ final class ICU4XDataProvider implements ffi.Finalizable {
   /// See the [Rust documentation for `get_static_provider`](https://docs.rs/icu_testdata/latest/icu_testdata/fn.get_static_provider.html) for more information.
   factory ICU4XDataProvider.static_() {
     final result = _ICU4XDataProvider_new_static();
-    return ICU4XDataProvider._(result);
+    return ICU4XDataProvider._(result, true);
   }
 
   /// This exists as a regression test for https://github.com/rust-diplomat/diplomat/issues/155
diff --git a/example/dart/lib/src/ICU4XFixedDecimal.g.dart b/example/dart/lib/src/ICU4XFixedDecimal.g.dart
index efb130603..34bfbe11d 100644
--- a/example/dart/lib/src/ICU4XFixedDecimal.g.dart
+++ b/example/dart/lib/src/ICU4XFixedDecimal.g.dart
@@ -9,8 +9,10 @@ part of 'lib.g.dart';
 final class ICU4XFixedDecimal implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  ICU4XFixedDecimal._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  ICU4XFixedDecimal._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_ICU4XFixedDecimal_destroy));
@@ -18,7 +20,7 @@ final class ICU4XFixedDecimal implements ffi.Finalizable {
   /// Construct an [`ICU4XFixedDecimal`] from an integer.
   factory ICU4XFixedDecimal(int v) {
     final result = _ICU4XFixedDecimal_new(v);
-    return ICU4XFixedDecimal._(result);
+    return ICU4XFixedDecimal._(result, true);
   }
 
   /// Multiply the [`ICU4XFixedDecimal`] by a given power of ten.
diff --git a/example/dart/lib/src/ICU4XFixedDecimalFormatter.g.dart b/example/dart/lib/src/ICU4XFixedDecimalFormatter.g.dart
index a0d50b179..2cacca5f2 100644
--- a/example/dart/lib/src/ICU4XFixedDecimalFormatter.g.dart
+++ b/example/dart/lib/src/ICU4XFixedDecimalFormatter.g.dart
@@ -11,8 +11,10 @@ part of 'lib.g.dart';
 final class ICU4XFixedDecimalFormatter implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  ICU4XFixedDecimalFormatter._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  ICU4XFixedDecimalFormatter._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_ICU4XFixedDecimalFormatter_destroy));
@@ -27,7 +29,7 @@ final class ICU4XFixedDecimalFormatter implements ffi.Finalizable {
     if (!result.isOk) {
       throw VoidError();
     }
-    return ICU4XFixedDecimalFormatter._(result.union.ok);
+    return ICU4XFixedDecimalFormatter._(result.union.ok, true);
   }
 
   /// Formats a [`ICU4XFixedDecimal`] to a string.
diff --git a/example/dart/lib/src/ICU4XLocale.g.dart b/example/dart/lib/src/ICU4XLocale.g.dart
index e096592c7..1ca9c095b 100644
--- a/example/dart/lib/src/ICU4XLocale.g.dart
+++ b/example/dart/lib/src/ICU4XLocale.g.dart
@@ -11,8 +11,10 @@ part of 'lib.g.dart';
 final class ICU4XLocale implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  ICU4XLocale._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  ICU4XLocale._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_ICU4XLocale_destroy));
@@ -23,7 +25,7 @@ final class ICU4XLocale implements ffi.Finalizable {
     final nameView = name.utf8View;
     final result = _ICU4XLocale_new(nameView.pointer(temp), nameView.length);
     temp.releaseAll();
-    return ICU4XLocale._(result);
+    return ICU4XLocale._(result, true);
   }
 }
 
diff --git a/feature_tests/c/include/Bar.h b/feature_tests/c/include/Bar.h
index f4467f2dd..f7a93e618 100644
--- a/feature_tests/c/include/Bar.h
+++ b/feature_tests/c/include/Bar.h
@@ -14,11 +14,13 @@ typedef struct Bar Bar;
 #ifdef __cplusplus
 } // namespace capi
 #endif
+#include "Foo.h"
 #ifdef __cplusplus
 namespace capi {
 extern "C" {
 #endif
 
+const Foo* Bar_foo(const Bar* self);
 void Bar_destroy(Bar* self);
 
 #ifdef __cplusplus
diff --git a/feature_tests/c2/include/Bar.h b/feature_tests/c2/include/Bar.h
index 1c6201f79..56943a954 100644
--- a/feature_tests/c2/include/Bar.h
+++ b/feature_tests/c2/include/Bar.h
@@ -6,6 +6,8 @@
 #include <stddef.h>
 #include <stdbool.h>
 #include "diplomat_runtime.h"
+#include "Foo.d.h"
+#include "Foo.h"
 
 #include "Bar.d.h"
 
@@ -15,6 +17,8 @@ extern "C" {
 #endif // __cplusplus
 
 
+const Foo* Bar_foo(const Bar* self);
+
 void Bar_destroy(Bar* self);
 
 
diff --git a/feature_tests/cpp/docs/source/lifetimes_ffi.rst b/feature_tests/cpp/docs/source/lifetimes_ffi.rst
index 16857dfc8..4644317fa 100644
--- a/feature_tests/cpp/docs/source/lifetimes_ffi.rst
+++ b/feature_tests/cpp/docs/source/lifetimes_ffi.rst
@@ -3,6 +3,7 @@
 
 .. cpp:class:: Bar
 
+
 .. cpp:struct:: BorrowedFields
 
     .. cpp:member:: std::u16string_view a
diff --git a/feature_tests/cpp/include/Bar.h b/feature_tests/cpp/include/Bar.h
index f4467f2dd..f7a93e618 100644
--- a/feature_tests/cpp/include/Bar.h
+++ b/feature_tests/cpp/include/Bar.h
@@ -14,11 +14,13 @@ typedef struct Bar Bar;
 #ifdef __cplusplus
 } // namespace capi
 #endif
+#include "Foo.h"
 #ifdef __cplusplus
 namespace capi {
 extern "C" {
 #endif
 
+const Foo* Bar_foo(const Bar* self);
 void Bar_destroy(Bar* self);
 
 #ifdef __cplusplus
diff --git a/feature_tests/cpp/include/Bar.hpp b/feature_tests/cpp/include/Bar.hpp
index 9298da47b..895516e97 100644
--- a/feature_tests/cpp/include/Bar.hpp
+++ b/feature_tests/cpp/include/Bar.hpp
@@ -11,6 +11,7 @@
 
 #include "Bar.h"
 
+class Foo;
 
 /**
  * A destruction policy for using Bar with std::unique_ptr.
@@ -32,5 +33,6 @@ class Bar {
   std::unique_ptr<capi::Bar, BarDeleter> inner;
 };
 
+#include "Foo.hpp"
 
 #endif
diff --git a/feature_tests/cpp2/include/Bar.d.hpp b/feature_tests/cpp2/include/Bar.d.hpp
index 089d2f72e..91e24a10d 100644
--- a/feature_tests/cpp2/include/Bar.d.hpp
+++ b/feature_tests/cpp2/include/Bar.d.hpp
@@ -10,10 +10,14 @@
 #include "diplomat_runtime.hpp"
 #include "Bar.d.h"
 
+class Foo;
+
 
 class Bar {
 public:
 
+  inline const Foo& foo() const;
+
   inline const capi::Bar* AsFFI() const;
   inline capi::Bar* AsFFI();
   inline static const Bar* FromFFI(const capi::Bar* ptr);
diff --git a/feature_tests/cpp2/include/Bar.h b/feature_tests/cpp2/include/Bar.h
index 1c6201f79..56943a954 100644
--- a/feature_tests/cpp2/include/Bar.h
+++ b/feature_tests/cpp2/include/Bar.h
@@ -6,6 +6,8 @@
 #include <stddef.h>
 #include <stdbool.h>
 #include "diplomat_runtime.h"
+#include "Foo.d.h"
+#include "Foo.h"
 
 #include "Bar.d.h"
 
@@ -15,6 +17,8 @@ extern "C" {
 #endif // __cplusplus
 
 
+const Foo* Bar_foo(const Bar* self);
+
 void Bar_destroy(Bar* self);
 
 
diff --git a/feature_tests/cpp2/include/Bar.hpp b/feature_tests/cpp2/include/Bar.hpp
index 346331677..caf1fd600 100644
--- a/feature_tests/cpp2/include/Bar.hpp
+++ b/feature_tests/cpp2/include/Bar.hpp
@@ -11,8 +11,14 @@
 #include <optional>
 #include "diplomat_runtime.hpp"
 #include "Bar.h"
+#include "Foo.hpp"
 
 
+inline const Foo& Bar::foo() const {
+  auto result = capi::Bar_foo(this->AsFFI());
+  return *Foo::FromFFI(result);
+}
+
 inline const capi::Bar* Bar::AsFFI() const {
   return reinterpret_cast<const capi::Bar*>(this);
 }
diff --git a/feature_tests/dart/lib/src/AttrOpaque1.g.dart b/feature_tests/dart/lib/src/AttrOpaque1.g.dart
index db49c97db..2c6d7c403 100644
--- a/feature_tests/dart/lib/src/AttrOpaque1.g.dart
+++ b/feature_tests/dart/lib/src/AttrOpaque1.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class AttrOpaque1 implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  AttrOpaque1._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  AttrOpaque1._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_AttrOpaque1_destroy));
diff --git a/feature_tests/dart/lib/src/AttrOpaque2.g.dart b/feature_tests/dart/lib/src/AttrOpaque2.g.dart
index b5156aa47..0b1de2993 100644
--- a/feature_tests/dart/lib/src/AttrOpaque2.g.dart
+++ b/feature_tests/dart/lib/src/AttrOpaque2.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class AttrOpaque2 implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  AttrOpaque2._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  AttrOpaque2._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_AttrOpaque2_destroy));
diff --git a/feature_tests/dart/lib/src/Bar.g.dart b/feature_tests/dart/lib/src/Bar.g.dart
index c729a120f..985cdc689 100644
--- a/feature_tests/dart/lib/src/Bar.g.dart
+++ b/feature_tests/dart/lib/src/Bar.g.dart
@@ -8,13 +8,24 @@ part of 'lib.g.dart';
 final class Bar implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  Bar._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  Bar._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_Bar_destroy));
+
+  Foo get foo {
+    final result = _Bar_foo(_underlying);
+    return Foo._(result, false);
+  }
 }
 
 @ffi.Native<ffi.Void Function(ffi.Pointer<ffi.Void>)>(isLeaf: true, symbol: 'Bar_destroy')
 // ignore: non_constant_identifier_names
 external void _Bar_destroy(ffi.Pointer<ffi.Void> self);
+
+@ffi.Native<ffi.Pointer<ffi.Opaque> Function(ffi.Pointer<ffi.Opaque>)>(isLeaf: true, symbol: 'Bar_foo')
+// ignore: non_constant_identifier_names
+external ffi.Pointer<ffi.Opaque> _Bar_foo(ffi.Pointer<ffi.Opaque> self);
diff --git a/feature_tests/dart/lib/src/Float64Vec.g.dart b/feature_tests/dart/lib/src/Float64Vec.g.dart
index 2c9c246fb..5cce123e6 100644
--- a/feature_tests/dart/lib/src/Float64Vec.g.dart
+++ b/feature_tests/dart/lib/src/Float64Vec.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class Float64Vec implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  Float64Vec._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  Float64Vec._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_Float64Vec_destroy));
@@ -19,7 +21,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v.float64View;
     final result = _Float64Vec_new(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   factory Float64Vec.bool(core.List<bool> v) {
@@ -27,7 +29,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v.boolView;
     final result = _Float64Vec_new_bool(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   factory Float64Vec.i16(core.List<int> v) {
@@ -35,7 +37,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v.int16View;
     final result = _Float64Vec_new_i16(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   factory Float64Vec.u16(core.List<int> v) {
@@ -43,7 +45,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v.uint16View;
     final result = _Float64Vec_new_u16(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   factory Float64Vec.isize(core.List<int> v) {
@@ -51,7 +53,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v.isizeView;
     final result = _Float64Vec_new_isize(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   factory Float64Vec.usize(core.List<int> v) {
@@ -59,7 +61,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v.usizeView;
     final result = _Float64Vec_new_usize(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   factory Float64Vec.f64BeBytes(ByteBuffer v) {
@@ -67,7 +69,7 @@ final class Float64Vec implements ffi.Finalizable {
     final vView = v;
     final result = _Float64Vec_new_f64_be_bytes(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return Float64Vec._(result);
+    return Float64Vec._(result, true);
   }
 
   void fillSlice(core.List<double> v) {
diff --git a/feature_tests/dart/lib/src/Foo.g.dart b/feature_tests/dart/lib/src/Foo.g.dart
index a12779fe3..9f80fcd7b 100644
--- a/feature_tests/dart/lib/src/Foo.g.dart
+++ b/feature_tests/dart/lib/src/Foo.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class Foo implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  Foo._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  Foo._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_Foo_destroy));
@@ -19,12 +21,12 @@ final class Foo implements ffi.Finalizable {
     final xView = x.utf8View;
     final result = _Foo_new(xView.pointer(temp), xView.length);
     temp.releaseAll();
-    return Foo._(result);
+    return Foo._(result, true);
   }
 
   Bar get getBar {
     final result = _Foo_get_bar(_underlying);
-    return Bar._(result);
+    return Bar._(result, true);
   }
 
   factory Foo.static_(String x) {
@@ -32,7 +34,7 @@ final class Foo implements ffi.Finalizable {
     final xView = x.utf8View;
     final result = _Foo_new_static(xView.pointer(temp), xView.length);
     temp.releaseAll();
-    return Foo._(result);
+    return Foo._(result, true);
   }
 
   BorrowedFieldsReturning get asReturning {
@@ -42,7 +44,7 @@ final class Foo implements ffi.Finalizable {
 
   factory Foo.extractFromFields(BorrowedFields fields) {
     final result = _Foo_extract_from_fields(fields._underlying);
-    return Foo._(result);
+    return Foo._(result, true);
   }
 }
 
diff --git a/feature_tests/dart/lib/src/MyString.g.dart b/feature_tests/dart/lib/src/MyString.g.dart
index fc2345534..561d0e777 100644
--- a/feature_tests/dart/lib/src/MyString.g.dart
+++ b/feature_tests/dart/lib/src/MyString.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class MyString implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  MyString._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  MyString._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_MyString_destroy));
@@ -19,7 +21,7 @@ final class MyString implements ffi.Finalizable {
     final vView = v.utf8View;
     final result = _MyString_new(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return MyString._(result);
+    return MyString._(result, true);
   }
 
   factory MyString.unsafe(String v) {
@@ -27,7 +29,7 @@ final class MyString implements ffi.Finalizable {
     final vView = v.utf8View;
     final result = _MyString_new_unsafe(vView.pointer(temp), vView.length);
     temp.releaseAll();
-    return MyString._(result);
+    return MyString._(result, true);
   }
 
   void setStr(String newStr) {
diff --git a/feature_tests/dart/lib/src/One.g.dart b/feature_tests/dart/lib/src/One.g.dart
index 95900ef2c..81cdb30e4 100644
--- a/feature_tests/dart/lib/src/One.g.dart
+++ b/feature_tests/dart/lib/src/One.g.dart
@@ -8,65 +8,67 @@ part of 'lib.g.dart';
 final class One implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  One._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  One._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_One_destroy));
 
   factory One.transitivity(One hold, One nohold) {
     final result = _One_transitivity(hold._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.cycle(Two hold, One nohold) {
     final result = _One_cycle(hold._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.manyDependents(One a, One b, Two c, Two d, Two nohold) {
     final result = _One_many_dependents(a._underlying, b._underlying, c._underlying, d._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.returnOutlivesParam(Two hold, One nohold) {
     final result = _One_return_outlives_param(hold._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.diamondTop(One top, One left, One right, One bottom) {
     final result = _One_diamond_top(top._underlying, left._underlying, right._underlying, bottom._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.diamondLeft(One top, One left, One right, One bottom) {
     final result = _One_diamond_left(top._underlying, left._underlying, right._underlying, bottom._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.diamondRight(One top, One left, One right, One bottom) {
     final result = _One_diamond_right(top._underlying, left._underlying, right._underlying, bottom._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.diamondBottom(One top, One left, One right, One bottom) {
     final result = _One_diamond_bottom(top._underlying, left._underlying, right._underlying, bottom._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.diamondAndNestedTypes(One a, One b, One c, One d, One nohold) {
     final result = _One_diamond_and_nested_types(a._underlying, b._underlying, c._underlying, d._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.implicitBounds(One explicitHold, One implicitHold, One nohold) {
     final result = _One_implicit_bounds(explicitHold._underlying, implicitHold._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 
   factory One.implicitBoundsDeep(One explicit, One implicit1, One implicit2, One nohold) {
     final result = _One_implicit_bounds_deep(explicit._underlying, implicit1._underlying, implicit2._underlying, nohold._underlying);
-    return One._(result);
+    return One._(result, true);
   }
 }
 
diff --git a/feature_tests/dart/lib/src/Opaque.g.dart b/feature_tests/dart/lib/src/Opaque.g.dart
index 190d7745f..8ede311e1 100644
--- a/feature_tests/dart/lib/src/Opaque.g.dart
+++ b/feature_tests/dart/lib/src/Opaque.g.dart
@@ -8,15 +8,17 @@ part of 'lib.g.dart';
 final class Opaque implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  Opaque._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  Opaque._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_Opaque_destroy));
 
   factory Opaque() {
     final result = _Opaque_new();
-    return Opaque._(result);
+    return Opaque._(result, true);
   }
 
   /// See the [Rust documentation for `something`](https://docs.rs/Something/latest/struct.Something.html#method.something) for more information.
diff --git a/feature_tests/dart/lib/src/OptionOpaque.g.dart b/feature_tests/dart/lib/src/OptionOpaque.g.dart
index fe42ebbcf..0322b5797 100644
--- a/feature_tests/dart/lib/src/OptionOpaque.g.dart
+++ b/feature_tests/dart/lib/src/OptionOpaque.g.dart
@@ -8,20 +8,22 @@ part of 'lib.g.dart';
 final class OptionOpaque implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  OptionOpaque._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  OptionOpaque._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_OptionOpaque_destroy));
 
   static OptionOpaque? new_(int i) {
     final result = _OptionOpaque_new(i);
-    return result.address == 0 ? null : OptionOpaque._(result);
+    return result.address == 0 ? null : OptionOpaque._(result, true);
   }
 
   static final OptionOpaque? none = () {
     final result = _OptionOpaque_new_none();
-    return result.address == 0 ? null : OptionOpaque._(result);
+    return result.address == 0 ? null : OptionOpaque._(result, true);
   }();
 
   static final OptionStruct struct = () {
diff --git a/feature_tests/dart/lib/src/OptionOpaqueChar.g.dart b/feature_tests/dart/lib/src/OptionOpaqueChar.g.dart
index c594bb3fe..7916aebd5 100644
--- a/feature_tests/dart/lib/src/OptionOpaqueChar.g.dart
+++ b/feature_tests/dart/lib/src/OptionOpaqueChar.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class OptionOpaqueChar implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  OptionOpaqueChar._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  OptionOpaqueChar._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_OptionOpaqueChar_destroy));
diff --git a/feature_tests/dart/lib/src/OptionStruct.g.dart b/feature_tests/dart/lib/src/OptionStruct.g.dart
index 010360a5e..de2ea2861 100644
--- a/feature_tests/dart/lib/src/OptionStruct.g.dart
+++ b/feature_tests/dart/lib/src/OptionStruct.g.dart
@@ -18,13 +18,13 @@ final class OptionStruct {
 
   OptionStruct._(this._underlying);
 
-  OptionOpaque? get a => _underlying.a.address == 0 ? null : OptionOpaque._(_underlying.a);
+  OptionOpaque? get a => _underlying.a.address == 0 ? null : OptionOpaque._(_underlying.a, true);
 
-  OptionOpaqueChar? get b => _underlying.b.address == 0 ? null : OptionOpaqueChar._(_underlying.b);
+  OptionOpaqueChar? get b => _underlying.b.address == 0 ? null : OptionOpaqueChar._(_underlying.b, true);
 
   int get c => _underlying.c;
 
-  OptionOpaque? get d => _underlying.d.address == 0 ? null : OptionOpaque._(_underlying.d);
+  OptionOpaque? get d => _underlying.d.address == 0 ? null : OptionOpaque._(_underlying.d, true);
 
   @override
   bool operator ==(Object other) =>
diff --git a/feature_tests/dart/lib/src/RefList.g.dart b/feature_tests/dart/lib/src/RefList.g.dart
index c9e72a0d3..2623b7f30 100644
--- a/feature_tests/dart/lib/src/RefList.g.dart
+++ b/feature_tests/dart/lib/src/RefList.g.dart
@@ -8,15 +8,17 @@ part of 'lib.g.dart';
 final class RefList implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  RefList._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  RefList._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_RefList_destroy));
 
   factory RefList.node(RefListParameter data) {
     final result = _RefList_node(data._underlying);
-    return RefList._(result);
+    return RefList._(result, true);
   }
 }
 
diff --git a/feature_tests/dart/lib/src/RefListParameter.g.dart b/feature_tests/dart/lib/src/RefListParameter.g.dart
index f4659584e..527165158 100644
--- a/feature_tests/dart/lib/src/RefListParameter.g.dart
+++ b/feature_tests/dart/lib/src/RefListParameter.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class RefListParameter implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  RefListParameter._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  RefListParameter._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_RefListParameter_destroy));
diff --git a/feature_tests/dart/lib/src/ResultOpaque.g.dart b/feature_tests/dart/lib/src/ResultOpaque.g.dart
index b739ecda2..b6ed21396 100644
--- a/feature_tests/dart/lib/src/ResultOpaque.g.dart
+++ b/feature_tests/dart/lib/src/ResultOpaque.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class ResultOpaque implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  ResultOpaque._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  ResultOpaque._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_ResultOpaque_destroy));
@@ -22,7 +24,7 @@ final class ResultOpaque implements ffi.Finalizable {
     if (!result.isOk) {
       throw ErrorEnum.values[result.union.err];
     }
-    return ResultOpaque._(result.union.ok);
+    return ResultOpaque._(result.union.ok, true);
   }
 
   /// 
@@ -33,7 +35,7 @@ final class ResultOpaque implements ffi.Finalizable {
     if (!result.isOk) {
       throw ErrorEnum.values[result.union.err];
     }
-    return ResultOpaque._(result.union.ok);
+    return ResultOpaque._(result.union.ok, true);
   }
 
   /// 
@@ -44,7 +46,7 @@ final class ResultOpaque implements ffi.Finalizable {
     if (!result.isOk) {
       throw ErrorEnum.values[result.union.err];
     }
-    return ResultOpaque._(result.union.ok);
+    return ResultOpaque._(result.union.ok, true);
   }
 
   /// 
@@ -55,7 +57,7 @@ final class ResultOpaque implements ffi.Finalizable {
     if (!result.isOk) {
       throw VoidError();
     }
-    return ResultOpaque._(result.union.ok);
+    return ResultOpaque._(result.union.ok, true);
   }
 
   /// 
@@ -66,7 +68,7 @@ final class ResultOpaque implements ffi.Finalizable {
     if (!result.isOk) {
       throw ErrorStruct._(result.union.err);
     }
-    return ResultOpaque._(result.union.ok);
+    return ResultOpaque._(result.union.ok, true);
   }
 
   /// 
@@ -75,7 +77,7 @@ final class ResultOpaque implements ffi.Finalizable {
   static void newInErr(int i) {
     final result = _ResultOpaque_new_in_err(i);
     if (!result.isOk) {
-      throw ResultOpaque._(result.union.err);
+      throw ResultOpaque._(result.union.err, true);
     }
   }
 
@@ -96,7 +98,7 @@ final class ResultOpaque implements ffi.Finalizable {
   static ErrorEnum newInEnumErr(int i) {
     final result = _ResultOpaque_new_in_enum_err(i);
     if (!result.isOk) {
-      throw ResultOpaque._(result.union.err);
+      throw ResultOpaque._(result.union.err, true);
     }
     return ErrorEnum.values[result.union.ok];
   }
diff --git a/feature_tests/dart/lib/src/Two.g.dart b/feature_tests/dart/lib/src/Two.g.dart
index 0f4236e6c..7c032346a 100644
--- a/feature_tests/dart/lib/src/Two.g.dart
+++ b/feature_tests/dart/lib/src/Two.g.dart
@@ -8,8 +8,10 @@ part of 'lib.g.dart';
 final class Two implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  Two._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  Two._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_Two_destroy));
diff --git a/feature_tests/dotnet/Lib/Generated/RawBar.cs b/feature_tests/dotnet/Lib/Generated/RawBar.cs
index 4618861f7..a55d8af91 100644
--- a/feature_tests/dotnet/Lib/Generated/RawBar.cs
+++ b/feature_tests/dotnet/Lib/Generated/RawBar.cs
@@ -16,6 +16,9 @@ public partial struct Bar
 {
     private const string NativeLib = "diplomat_feature_tests";
 
+    [DllImport(NativeLib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "Bar_foo", ExactSpelling = true)]
+    public static unsafe extern Foo* Foo(Bar* self);
+
     [DllImport(NativeLib, CallingConvention = CallingConvention.Cdecl, EntryPoint = "Bar_destroy", ExactSpelling = true)]
     public static unsafe extern void Destroy(Bar* self);
 }
diff --git a/feature_tests/js/api/Bar.d.ts b/feature_tests/js/api/Bar.d.ts
index 327e5a611..29c81c708 100644
--- a/feature_tests/js/api/Bar.d.ts
+++ b/feature_tests/js/api/Bar.d.ts
@@ -1,5 +1,10 @@
+import { Foo } from "./Foo";
 
 /**
  */
 export class Bar {
+
+  /**
+   */
+  foo(): Foo;
 }
diff --git a/feature_tests/js/api/Bar.mjs b/feature_tests/js/api/Bar.mjs
index 66613b0e3..fd8a9cc22 100644
--- a/feature_tests/js/api/Bar.mjs
+++ b/feature_tests/js/api/Bar.mjs
@@ -1,5 +1,6 @@
 import wasm from "./diplomat-wasm.mjs"
 import * as diplomatRuntime from "./diplomat-runtime.mjs"
+import { Foo } from "./Foo.mjs"
 
 const Bar_box_destroy_registry = new FinalizationRegistry(underlying => {
   wasm.Bar_destroy(underlying);
@@ -14,4 +15,8 @@ export class Bar {
       Bar_box_destroy_registry.register(this, underlying);
     }
   }
+
+  foo() {
+    return new Foo(wasm.Bar_foo(this.underlying), false, [this]);
+  }
 }
diff --git a/feature_tests/js/docs/source/lifetimes_ffi.rst b/feature_tests/js/docs/source/lifetimes_ffi.rst
index 3bb763315..6b1865aac 100644
--- a/feature_tests/js/docs/source/lifetimes_ffi.rst
+++ b/feature_tests/js/docs/source/lifetimes_ffi.rst
@@ -3,6 +3,8 @@
 
 .. js:class:: Bar
 
+    .. js:method:: foo()
+
 .. js:class:: BorrowedFields
 
     .. js:attribute:: a
diff --git a/feature_tests/src/lifetimes.rs b/feature_tests/src/lifetimes.rs
index 16f4f8785..a0b6fa9d2 100644
--- a/feature_tests/src/lifetimes.rs
+++ b/feature_tests/src/lifetimes.rs
@@ -39,11 +39,12 @@ pub mod ffi {
     }
 
     // FIXME(#191): This test breaks the C++ codegen
-    // impl<'b, 'a: 'b> Bar<'b, 'a> {
-    //     pub fn foo(&'b self) -> &'b Foo<'a> {
-    //         self.0
-    //     }
-    // }
+    impl<'b, 'a: 'b> Bar<'b, 'a> {
+        #[diplomat::skip_if_unsupported]
+        pub fn foo(&'b self) -> &'b Foo<'a> {
+            self.0
+        }
+    }
 
     #[derive(Copy, Clone)]
     #[diplomat::opaque]
diff --git a/macro/src/lib.rs b/macro/src/lib.rs
index 19d35e645..1507c71fa 100644
--- a/macro/src/lib.rs
+++ b/macro/src/lib.rs
@@ -273,7 +273,11 @@ impl AttributeInfo {
                     } else if seg == "out" {
                         is_out = true;
                         return false;
-                    } else if seg == "rust_link" || seg == "out" || seg == "attr" {
+                    } else if seg == "rust_link"
+                        || seg == "out"
+                        || seg == "attr"
+                        || seg == "skip_if_unsupported"
+                    {
                         // diplomat-tool reads these, not diplomat::bridge.
                         // throw them away so rustc doesn't complain about unknown attributes
                         return false;
diff --git a/tool/src/cpp/docs.rs b/tool/src/cpp/docs.rs
index 4eae1c6ac..34058f6c9 100644
--- a/tool/src/cpp/docs.rs
+++ b/tool/src/cpp/docs.rs
@@ -161,6 +161,12 @@ pub fn gen_method_docs<W: fmt::Write>(
     docs_url_gen: &ast::DocsUrlGenerator,
     out: &mut W,
 ) -> fmt::Result {
+    if method.attrs.skip_if_unsupported
+        && matches!(method.return_type, Some(ast::TypeName::Reference(..)))
+    {
+        // We don't support returning references
+        return Ok(());
+    }
     // This method should rearrange the writeable
     let rearranged_writeable = method.is_writeable_out() && writeable_to_string;
 
diff --git a/tool/src/cpp/structs.rs b/tool/src/cpp/structs.rs
index 600b6e562..414ca83d0 100644
--- a/tool/src/cpp/structs.rs
+++ b/tool/src/cpp/structs.rs
@@ -177,6 +177,12 @@ fn gen_method<W: fmt::Write>(
     docs_url_gen: &ast::DocsUrlGenerator,
     out: &mut W,
 ) -> fmt::Result {
+    if method.attrs.skip_if_unsupported
+        && matches!(method.return_type, Some(ast::TypeName::Reference(..)))
+    {
+        // We don't support returning references
+        return Ok(());
+    }
     // This method should rearrange the writeable
     let rearranged_writeable = method.is_writeable_out() && writeable_to_string;
 
diff --git a/tool/src/dart/mod.rs b/tool/src/dart/mod.rs
index e532ef24b..c6b2fe5da 100644
--- a/tool/src/dart/mod.rs
+++ b/tool/src/dart/mod.rs
@@ -691,12 +691,11 @@ impl<'a, 'cx> TyGenContext<'a, 'cx> {
                 let id = op.tcx_id.into();
                 let type_name = self.formatter.fmt_type_name(id);
 
-                match (op.owner.is_owned(), op.is_optional()) {
-                    (false, _) => unimplemented!(),
-                    (true, false) => format!("{type_name}._({var_name})").into(),
-                    (true, true) => {
-                        format!("{var_name}.address == 0 ? null : {type_name}._({var_name})").into()
-                    }
+                let owned = op.owner.is_owned();
+                if op.is_optional() {
+                    format!("{var_name}.address == 0 ? null : {type_name}._({var_name}, {owned})").into()
+                } else {
+                    format!("{type_name}._({var_name}, {owned})").into()
                 }
             }
             Type::Struct(ref st) => {
diff --git a/tool/src/dotnet/idiomatic.rs b/tool/src/dotnet/idiomatic.rs
index 1ad5184c0..30a49207b 100644
--- a/tool/src/dotnet/idiomatic.rs
+++ b/tool/src/dotnet/idiomatic.rs
@@ -313,6 +313,12 @@ fn gen_method(
     docs_url_gen: &ast::DocsUrlGenerator,
     out: &mut CodeWriter,
 ) -> fmt::Result {
+    if method.attrs.skip_if_unsupported
+        && matches!(method.return_type, Some(ast::TypeName::Reference(..)))
+    {
+        // We don't support returning references
+        return Ok(());
+    }
     // This method should rearrange the writeable
     let rearranged_writeable = method.is_writeable_out() && writeable_to_string;
 
diff --git a/tool/templates/dart/opaque.dart.jinja b/tool/templates/dart/opaque.dart.jinja
index a28ed0dc4..97f63fb10 100644
--- a/tool/templates/dart/opaque.dart.jinja
+++ b/tool/templates/dart/opaque.dart.jinja
@@ -4,8 +4,10 @@
 final class {{type_name}} implements ffi.Finalizable {
   final ffi.Pointer<ffi.Opaque> _underlying;
 
-  {{type_name}}._(this._underlying) {
-    _finalizer.attach(this, _underlying.cast());
+  {{type_name}}._(this._underlying, bool isOwned) {
+    if (isOwned) {
+      _finalizer.attach(this, _underlying.cast());
+    }
   }
 
   static final _finalizer = ffi.NativeFinalizer(ffi.Native.addressOf(_{{destructor}}));