Issue description

The code following C# code

public void UnmanagedT<T>() where T : unmanaged { }

generates the following IL code:

.method public hidebysig instance void UnmanagedT<valuetype .ctor (class [mscorlib]System.ValueType modreq([mscorlib]System.Runtime.InteropServices.UnmanagedType)) T> () cil managed { .param type T .custom instance void System.Runtime.CompilerServices.IsUnmanagedAttribute::.ctor() = ( 01 00 00 00 ) .maxstack 8 IL_0000: ret }

which expect any compilers wanting to use the method to know that the type parameter T has to meet certain requirements.

With the System.Runtime.CompilerServices.IsVolatile type it is documented how & what the modreq does, it should be the same here. It would also be good if System.Runtime.CompilerServices.IsExternalInit (and any others missing it) got the same documentation.

I'm looking on https://docs.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.unmanagedtype?view=net-6.0.

Target framework

• .NET Core 1.0+
• .NET Framework 1.1+
• .NET Standard 1.1+