retaining block and all of the enclosing blocks are non-escaping.
If the block implicitly retaining self doesn't escape, there is no risk
of creating retain cycles, so clang shouldn't diagnose it and force
users to add self-> to silence the diagnostic.
Also, fix a bug where clang was failing to diagnose an implicitly
retained self inside a c++ lambda nested inside a block.
rdar://problem/25059955
Differential Revision: https://reviews.llvm.org/D60736
llvm-svn: 358624
Akira Hatanaka