Don't propagate the 'availability' attribute through declaration

merging for overrides. One might want to make a method's availability
in a superclass different from that of its subclass. Fixes
<rdar://problem/10166223>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140406 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaDecl.cpp

@@ -1493,9 +1493,11 @@ static void mergeDeclAttributes(Decl *newDecl, const Decl *oldDecl,
   for (specific_attr_iterator<InheritableAttr>
        i = oldDecl->specific_attr_begin<InheritableAttr>(),
        e = oldDecl->specific_attr_end<InheritableAttr>(); i != e; ++i) {
-    // Ignore deprecated and unavailable attributes if requested.
+    // Ignore deprecated/unavailable/availability attributes if requested.
     if (!mergeDeprecation &&
-        (isa<DeprecatedAttr>(*i) || isa<UnavailableAttr>(*i)))
+        (isa<DeprecatedAttr>(*i) || 
+         isa<UnavailableAttr>(*i) ||
+         isa<AvailabilityAttr>(*i)))
       continue;
 
     if (!DeclHasAttr(newDecl, *i)) {

test/SemaObjC/attr-availability.m

@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+@interface A
+- (void)method __attribute__((availability(macosx,introduced=10.1,deprecated=10.2)));
+@end
+
+@interface B : A
+- (void)method;
+@end
+
+void f(A *a, B *b) {
+  [a method]; // expected-warning{{'method' is deprecated: first deprecated in Mac OS X 10.2}}
+  [b method];
+}