Cxx to Swift interop - issue with Array and Int type - "type cannot be used in a Swift generic context"

[litewrap]

Description

Issue when working with Swift Array from C++.
"type cannot be used in a Swift generic context"

Steps to reproduce

// Swift

@_expose(Cxx, "makeArrayInt")
public func makeArrayInt() -> [Int] {
    return [1, 2, 3, 4, 5]
}

// C++

auto result = MySwiftLib::makeArrayInt();

./MySwiftLib-Swift.h:785:1: error: static_assert failed due to requirement 'swift::isUsableInGenericContext<long>' "type cannot be used in a Swift generic context"
static_assert(swift::isUsableInGenericContext<T_0_0>, "type cannot be used in a Swift generic context");
^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./MySwiftLib-Swift.h:4064:33: note: in instantiation of template class 'Swift::Array<long>' requested here
inline Swift::Array<swift::Int> makeArrayInt() noexcept SWIFT_WARN_UNUSED_RESULT {
                                ^
./MySwiftLib-Swift.h:1031:1: error: static_assert failed due to requirement 'swift::isUsableInGenericContext<long>' "type cannot be used in a Swift generic context"
static_assert(swift::isUsableInGenericContext<T_0_0>, "type cannot be used in a Swift generic context");
^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./MySwiftLib-Swift.h:4065:24: note: in instantiation of template class 'Swift::_impl::_impl_Array<long>' requested here
  return Swift::_impl::_impl_Array<swift::Int>::returnNewValue([&](char * _Nonnull result) {
                       

Compiling C++ with -std=c++20

In file included from main.cpp:7:
./MySwiftLib-Swift.h:4064:15: error: constraints not satisfied for class template 'Array' [with T_0_0 = long]
inline Swift::Array<swift::Int> makeArrayInt() noexcept SWIFT_WARN_UNUSED_RESULT {
              ^~~~~~~~~~~~~~~~~
./MySwiftLib-Swift.h:780:10: note: because 'swift::isUsableInGenericContext<long>' evaluated to false
requires swift::isUsableInGenericContext<T_0_0>
         ^
./MySwiftLib-Swift.h:4065:24: error: constraints not satisfied for class template '_impl_Array' [with T_0_0 = long]
  return Swift::_impl::_impl_Array<swift::Int>::returnNewValue([&](char * _Nonnull result) {
                       ^~~~~~~~~~~~~~~~~~~~~~~
./MySwiftLib-Swift.h:1026:10: note: because 'swift::isUsableInGenericContext<long>' evaluated to false
requires swift::isUsableInGenericContext<T_0_0>
         ^

Note that using Int64 instead of Int in the Swift code will work calling from C++.

[AnthonyLatsis]

@egorzhdan Should this be qualified as a bug or feature request?

[hyp]

Potentially fixed in - #67241