Rework how ObjC method inherit deprecated/availability.

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

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e9116bc91a5..84d992c8788 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -2769,7 +2769,10 @@ void Sema::mergeObjCMethodDecls(ObjCMethodDecl *newMethod,
                                 ObjCMethodDecl *oldMethod) {
 
   // Merge the attributes, including deprecated/unavailable
-  mergeDeclAttributes(newMethod, oldMethod, AMK_Override);
+  AvailabilityMergeKind MergeKind =
+    isa<ObjCImplDecl>(newMethod->getDeclContext()) ? AMK_Redeclaration
+                                                   : AMK_Override;
+  mergeDeclAttributes(newMethod, oldMethod, MergeKind);
 
   // Merge attributes from the parameters.
   ObjCMethodDecl::param_const_iterator oi = oldMethod->param_begin(),