of a method that was declared in an invalid interface
This commit fixes an infinite loop that occurs when clang tries to iterate over
redeclaration of a method that was declared in an invalid @interface. The
existing validity checks don't catch this as that @interface is a duplicate of
a previously declared valid @interface declaration, so we have to verify that
the found redeclaration is in a valid declaration context.
rdar://29220965
Differential Revision: https://reviews.llvm.org/D26664
llvm-svn: 287530