[Sema][ObjC] Don't emit availability diagnostics for categories extending unavailable interfaces

[erik.pilkington]

Summary

Previously, @implementations of categories that extended unavailable/deprecated/partial @interfaces triggered availability diagnostics. There was no way to turn this off, as we check the use of the unavailable decl outside of the context of the @implementation, so attaching an attribute to the category @interface doesn't do anything. Moreover, this diagnostic can't actually catch any bugs even if it worked correctly, there is no way to use stuff declared in a category without referencing the extended @interface (AFAIK, I'm not fluent in Objective-C), which will trigger the diagnostic.

rdar://32427296

Thanks for taking a look,
Erik

[arphaman]

LGTM, Thanks

lib/Sema/SemaDeclObjC.cpp

   } else if (RequireCompleteType(ClassLoc, Context.getObjCInterfaceType(IDecl),
                                  diag::err_undef_interface)) {
     CDecl->setInvalidDecl();
   }
 
   // FIXME: PushOnScopeChains?
   CurContext->addDecl(CDecl);
 
-  // If the interface is deprecated/unavailable, warn/error about it.
-  if (IDecl)
-    DiagnoseUseOfDecl(IDecl, ClassLoc);
-
   // If the interface has the objc_runtime_visible attribute, we
   // cannot implement a category for it.
   if (IDecl && IDecl->hasAttr<ObjCRuntimeVisibleAttr>()) {
     Diag(ClassLoc, diag::err_objc_runtime_visible_category)
       << IDecl->getDeclName();
   }
 
   /// Check that CatName, category name, is not used in another implementation.

test/SemaObjC/attr-deprecated.m

 
 int t5() {
   Bar *f;
   f.FooBar = 1;    // expected-warning {{'FooBar' is deprecated}}
   return f.FooBar; // expected-warning {{'FooBar' is deprecated}}
 }
 
 
-__attribute ((deprecated)) // expected-note 2 {{'DEPRECATED' has been explicitly marked deprecated here}}
+__attribute ((deprecated)) // expected-note {{'DEPRECATED' has been explicitly marked deprecated here}}
 @interface DEPRECATED { 
   @public int ivar; 
   DEPRECATED *ivar2; // no warning.
 } 
 - (int) instancemethod;
 - (DEPRECATED *) meth; // no warning.
 @property  int prop; 
 @end
 
 @interface DEPRECATED (Category) // no warning.
 - (DEPRECATED *) meth2; // no warning.
 @end
 
 @interface DEPRECATED (Category2) // no warning.
+- (id)meth;
 @end
 
-@implementation DEPRECATED (Category2) // expected-warning {{'DEPRECATED' is deprecated}}
+__attribute__((deprecated))
+void depr_function();
+
+@implementation DEPRECATED (Category2) // no warning
+- (id)meth {
+  depr_function(); // no warning.
+  return 0;
+}
 @end
 
 @interface NS : DEPRECATED  // expected-warning {{'DEPRECATED' is deprecated}}
 @end
 
 
 @interface Test2
 @property int test2 __attribute__((deprecated)); // expected-note 2 {{property 'test2' is declared deprecated here}} expected-note 3 {{'test2' has been explicitly marked deprecated here}} \

test/SemaObjC/class-unavail-warning.m

 // RUN: %clang_cc1  -fsyntax-only -fblocks -triple x86_64-apple-darwin10 -verify %s
 // rdar://9092208
 
 __attribute__((unavailable("not available")))
-@interface MyClass { // expected-note 8 {{'MyClass' has been explicitly marked unavailable here}}
+@interface MyClass { // expected-note 7 {{'MyClass' has been explicitly marked unavailable here}}
 @public
     void *_test;
     MyClass *ivar; // no error.
 }
 
 - (id)self;
 - new;
 + (void)addObject:(id)anObject;

 
 @interface MyClass (Cat1)
 - (MyClass *)meth; // no error.
 @end
 
 @interface MyClass (Cat2) // no error.
 @end
 
-@implementation MyClass (Cat2) // expected-error {{unavailable}}
+@implementation MyClass (Cat2) // no error.
 @end
 
 int main() {
  [MyClass new]; // expected-error {{'MyClass' is unavailable: not available}}
  [MyClass self]; // expected-error {{'MyClass' is unavailable: not available}}
  [MyClass addObject:((void *)0)]; // expected-error {{'MyClass' is unavailable: not available}}
 
  MyClass *foo = [MyClass new]; // expected-error 2 {{'MyClass' is unavailable: not available}}

test/SemaObjC/warn-deprecated-implementations.m

 @interface A(CAT)
 - (void) G __attribute__((deprecated)); 
 @end
 
 @implementation A(CAT)
 - (void) G {}   // No warning, implementing its own deprecated method
 @end
 
-__attribute__((deprecated)) // expected-note 2 {{'CL' has been explicitly marked deprecated here}}
+__attribute__((deprecated)) // expected-note {{'CL' has been explicitly marked deprecated here}}
 @interface CL // expected-note 2 {{class declared here}} 
 @end
 
 @implementation CL // expected-warning {{Implementing deprecated class}}
 @end
 
-@implementation CL ( SomeCategory ) // expected-warning {{'CL' is deprecated}} \
-                                    // expected-warning {{Implementing deprecated category}}
+@implementation CL (SomeCategory) // expected-warning {{Implementing deprecated category}}
 @end
 
 @interface CL_SUB : CL // expected-warning {{'CL' is deprecated}}
 @end
 
 @interface BASE
 - (void) B __attribute__((deprecated)); // expected-note {{method 'B' declared here}}
 @end