Expected type 'System.Runtime.CompilerServices.ICastable' not found in module

[kant2002]

I messing up with custom runtime, and something start falling.

EXEC : error : Expected type 'System.Runtime.CompilerServices.ICastable' not found in module 'EfiRuntime' [D:\d\kant\my\EfiTools\UefiSnake\UefiSnake.csproj]
  System.InvalidOperationException: Expected type 'System.Runtime.CompilerServices.ICastable' not found in module 'EfiRuntime'
     at Internal.IL.HelperExtensions.GetKnownType(ModuleDesc module, String namespace, String name)
     at ILCompiler.DependencyAnalysis.NodeFactory.get_ICastableInterface()
     at ILCompiler.DependencyAnalysis.EETypeNode.OutputFlags(NodeFactory factory, ObjectDataBuilder& objData)
     at ILCompiler.DependencyAnalysis.EETypeNode.GetData(NodeFactory factory, Boolean relocsOnly)
     at ILCompiler.DependencyAnalysis.ObjectNode.GetStaticDependencies(NodeFactory factory)
     at ILCompiler.DependencyAnalysisFramework.DependencyAnalyzer`2.GetStaticDependenciesImpl(DependencyNodeCore`1 node)
     at ILCompiler.DependencyAnalysisFramework.DependencyAnalyzer`2.ProcessMarkStack()
     at ILCompiler.DependencyAnalysisFramework.DependencyAnalyzer`2.ComputeMarkedNodes()
     at ILCompiler.ILScanner.ILCompiler.IILScanner.Scan()
     at ILCompiler.Program.Run(String[] args)
     at ILCompiler.Program.Main(String[] args)

Seems to be it is falling in this code

corert/src/ILCompiler.Compiler/src/Compiler/DependencyAnalysis/EETypeNode.cs

Lines 563 to 573 in bee1832

	if (!(this is CanonicalDefinitionEETypeNode))
	{
	foreach (DefType itf in _type.RuntimeInterfaces)
	{
	if (itf == factory.ICastableInterface)
	{
	flags |= (UInt16)EETypeFlags.ICastableFlag;
	break;
	}
	}
	}

because I do not implement ICastable.

If I do not have ICastable defined, maybe I do not care, and Node flag EETypeFlags.ICastableFlag should not be set at all?

[MichalStrehovsky]

If I do not have ICastable defined, maybe I do not care, and Node flag EETypeFlags.ICastableFlag should not be set at all?

Yep - we can either change the compiler so that the absence of ICastable interface is not fatal, or you can just add a dummy ICastable to your corelib (it shouldn't need any methods on it, as long as no type implements the interface).