Fix an obvious goof that caused us to only see the top level of return types
when checking for covariance. Added some fun test cases, fixes PR6110.

This felt obvious enough to just commit. ;] Let me know if anything needs
tweaking.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@94173 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed