AbstractTransformer #1419: a type is turned to raw if it has a contravariant tp with Nothing
BoxingVisitor #1419: make sure members/invocations on raw types are marked as erased, invocation on raw types
Decl: squash NPE
ExpressionTransformer: variable is gone ceylon/ceylon.language#334
Updated tests for ceylon/ceylon.language#334: variable is gone
Test for #1419
Test .src: fallout from #1419

Not too sure why...