Sometimes enums are not blittable on Blazor WASM

[mattleibow]

Description

I have this pinvoke code:

[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
internal unsafe delegate UnicodeGeneralCategory UnicodeGeneralCategoryProxyDelegate(IntPtr ufuncs, UInt32 unicode, void* user_data);

And compiler gives this:

C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\6.0.0\Sdk\WasmApp.Native.targets(239,5): error : The return type 'BlazorApp8.UnicodeGeneralCategory' of pinvoke callback method 'BlazorApp8.UnicodeGeneralCategory GeneralCategoryProxyImplementation(System.IntPtr, System.UInt32, System.Void*)' needs to be blittable.

Reproduction Steps

BlazorApp8.zip

Expected behavior

Compiles

Actual behavior

Error

Regression?

Probably not.

Known Workarounds

Make the return type an int and then cast to an enum.

Configuration

No response

Other information

No response

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[radical]

Dupe of #61144 .