Generator crash on adding ExclusiveTo attribute

[asklar]

The generator will try adding ExclusiveTo but pass a string (class name) instead of a Type

CsWinRT/src/Authoring/WinRT.SourceGenerator/WinRTTypeWriter.cs

Lines 1566 to 1579 in ad6adcb

	private void AddExclusiveToAttribute(EntityHandle interfaceHandle, string className)
	{
	List<ITypeSymbol> types = new List<ITypeSymbol>
	{
	Model.Compilation.GetTypeByMetadataName("System.Type")
	};
	List<object> arguments = new List<object>
	{
	className
	};
	AddCustomAttributes("Windows.Foundation.Metadata.ExclusiveToAttribute", types, arguments, interfaceHandle);
	}