After issuing diagnostics on circular protocol list,
don't build circular AST in protocol's protocol list 
when user code has introduced it. Indexer and other   
clients may crash. // rdar://9221614


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@131254 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed