New rule:
- Method decls in @implementation are considered "redeclarations"
and inherit deprecated/availability from the @interface.
- All other cases are consider overrides, which do not inherit
deprecated/availability. For example:
(a) @interface redeclares a method in an adopted protocol.
(b) A subclass redeclares a method in a superclass.
(c) A protocol redeclares a method from another protocol it adopts.
The idea is that API authors should have the ability to easily
move availability/deprecated up and down a class/protocol hierarchy.
A redeclaration means that the availability/deprecation is a blank
slate.
Fixes <rdar://problem/13574571>
llvm-svn: 178937