Sema::ActOnStartProtocolInterface(): Make sure the protocol decl has a valid start location.

The following case resulted in an invalid start location:

// start location not being set for ObjCProtocolDecl AST (when a forward reference is in scope).
@protocol Buggy;

@protocol Buggy 
@optional
- whatever;
@end

llvm-svn: 54740
1 file changed
tree: 80fecdad61c8c204f7f24e14c4f3a765a1b7e456
  1. clang/
  2. llvm/