Warnings for AOT unsafe interop are incomplete best effort currently: #74630 (comment)

• Generate warnings for unsafe interop in marshalled structs
• Generate warnings for AOT unsafe marshallers like AsAny and LayoutClass
• Use actual marshaller kind to produce the warning instead of the approximation at

  runtime/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/Dataflow/ReflectionMethodBodyScanner.cs

  Lines 566 to 643 in 2201016

  	static bool IsComInterop(MarshalAsDescriptor? marshalInfoProvider, TypeDesc parameterType)
  	{
  	// This is best effort. One can likely find ways how to get COM without triggering these alarms.
  	// AsAny marshalling of a struct with an object-typed field would be one, for example.
  	// This logic roughly corresponds to MarshalInfo::MarshalInfo in CoreCLR,
  	// not trying to handle invalid cases and distinctions that are not interesting wrt
  	// "is this COM?" question.
  	NativeTypeKind nativeType = NativeTypeKind.Default;
  	if (marshalInfoProvider != null)
  	{
  	nativeType = marshalInfoProvider.Type;
  	}
  	if (nativeType == NativeTypeKind.IUnknown || nativeType == NativeTypeKind.IDispatch || nativeType == NativeTypeKind.Intf)
  	{
  	// This is COM by definition
  	return true;
  	}
  	if (nativeType == NativeTypeKind.Default)
  	{
  	TypeSystemContext context = parameterType.Context;
  	if (parameterType.IsPointer)
  	return false;
  	while (parameterType.IsParameterizedType)
  	parameterType = ((ParameterizedType)parameterType).ParameterType;
  	if (parameterType.IsWellKnownType(Internal.TypeSystem.WellKnownType.Array))
  	{
  	// System.Array marshals as IUnknown by default
  	return true;
  	}
  	else if (parameterType.IsWellKnownType(Internal.TypeSystem.WellKnownType.String) ||
  	InteropTypes.IsStringBuilder(context, parameterType))
  	{
  	// String and StringBuilder are special cased by interop
  	return false;
  	}
  	if (parameterType.IsValueType)
  	{
  	// Value types don't marshal as COM
  	return false;
  	}
  	else if (parameterType.IsInterface)
  	{
  	// Interface types marshal as COM by default
  	return true;
  	}
  	else if (parameterType.IsDelegate || parameterType.IsWellKnownType(Internal.TypeSystem.WellKnownType.MulticastDelegate)
  	|| parameterType == context.GetWellKnownType(Internal.TypeSystem.WellKnownType.MulticastDelegate).BaseType)
  	{
  	// Delegates are special cased by interop
  	return false;
  	}
  	else if (InteropTypes.IsCriticalHandle(context, parameterType))
  	{
  	// Subclasses of CriticalHandle are special cased by interop
  	return false;
  	}
  	else if (InteropTypes.IsSafeHandle(context, parameterType))
  	{
  	// Subclasses of SafeHandle are special cased by interop
  	return false;
  	}
  	else if (parameterType is MetadataType mdType && !mdType.IsSequentialLayout && !mdType.IsExplicitLayout)
  	{
  	// Rest of classes that don't have layout marshal as COM
  	return true;
  	}
  	}
  	return false;
  	}

• Steer people towards P/Invoke source generator by the warning text