[Sema] Fix assertion hit while trying to do constant evaluation for a dependent expression
inside a GNU statement expression.

rdar://16064952

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201468 91177308-0d34-0410-b5e6-96231b3b80d8
DebugInfo: imported_decl/using declarations at namespace scope

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@201470 91177308-0d34-0410-b5e6-96231b3b80d8