Checking whether a type is built-in

[NSExceptional]

Is it possible to check whether a type is a built-in type without comparing it to each KnownMetadata.Builtin? I thought this is what the isPOD flag was for, but I've just learned it's not

[Azoy]

You can check if the type is OpaqueMetadata because those are the only ones who are opaque as of now. isPOD means "plain old datatype" so I believe things like structs, enums, and tuples, etc.