Consider conversions of Objective-C pointers to 'id' to be basically of

the same rank as conversions of normal pointers to 'void*'.

Also, resurrect a test case.

Fixes rdar://problem/8592139

llvm-svn: 117354

clang/lib/Sema/SemaOverload.cpp

@@ -200,6 +200,9 @@ bool StandardConversionSequence::isPointerConversionToBool() const {
 /// conversion is a conversion of a pointer to a void pointer. This is
 /// used as part of the ranking of standard conversion sequences (C++
 /// 13.3.3.2p4).
+///
+/// Note that we treat conversions of Objective-C pointers to
+/// unqualified 'id' as having this same rank.
 bool
 StandardConversionSequence::
 isPointerConversionToVoidPointer(ASTContext& Context) const {
@@ -212,9 +215,15 @@ isPointerConversionToVoidPointer(ASTContext& Context) const {
   if (First == ICK_Array_To_Pointer)
     FromType = Context.getArrayDecayedType(FromType);
 
-  if (Second == ICK_Pointer_Conversion && FromType->isPointerType())
+  if (Second == ICK_Pointer_Conversion && FromType->isPointerType()) {
     if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
       return ToPtrType->getPointeeType()->isVoidType();
+  } else if (Second == ICK_Pointer_Conversion &&
+             FromType->isObjCObjectPointerType()) {
+    if (const ObjCObjectPointerType *ToPtrType =
+          ToType->getAs<ObjCObjectPointerType>())
+      return ToPtrType->isObjCIdType();
+  }
 
   return false;
 }

clang/test/SemaObjCXX/overload.mm

@@ -1,5 +1,4 @@
 // RUN: %clang_cc1 -fsyntax-only -verify %s
-// XFAIL: *
 @interface Foo
 @end
 
@@ -28,17 +27,20 @@ void func(id);
 @interface C <P1>
 @end
 
-int& f(A*);
-float& f(B*);
+int& f(A*); // expected-note {{candidate}}
+float& f(B*); // expected-note {{candidate}}
 void g(A*);
 
 int& h(A*);
 float& h(id);
 
-void test(A* a, B* b, id val) {
+void test0(A* a, B* b, id val) {
   int& i1 = f(a);
   float& f1 = f(b);
-  float& f2 = f(val);
+
+  // GCC succeeds here, which is clearly ridiculous.
+  float& f2 = f(val); // expected-error {{ambiguous}}
+
   g(a);
   g(b);
   g(val);
@@ -47,36 +49,45 @@ void test(A* a, B* b, id val) {
   //  int& i3 = h(b); FIXME: we match GCC here, but shouldn't this work?
 }
 
-void downcast_test(A* a, A** ap) {
-  B* b = a; // expected-warning{{incompatible pointer types initializing 'B *', expected 'A *'}}
-  b = a;  // expected-warning{{incompatible pointer types assigning 'B *', expected 'A *'}}
-
-  B** bp = ap; // expected-warning{{incompatible pointer types initializing 'B **', expected 'A **'}}
-  bp = ap; // expected-warning{{incompatible pointer types assigning 'B **', expected 'A **'}}
+// We make these errors instead of warnings.  Is that okay?
+void test1(A* a) {
+  B* b = a; // expected-error{{cannot initialize a variable of type 'B *' with an lvalue of type 'A *'}}
+  B *c; c = a; // expected-error{{assigning to 'B *' from incompatible type 'A *'}}
 }
 
-int& cv(A*);
-float& cv(const A*);
-int& cv2(void*);
-float& cv2(const void*);
+void test2(A** ap) {
+  B** bp = ap; // expected-warning{{incompatible pointer types converting 'A **' to type 'B **'}}
+  bp = ap; // expected-warning{{incompatible pointer types assigning to 'A **' from 'B **'}}
+}
+
+// FIXME: we should either allow overloading here or give a better diagnostic
+int& cv(A*); // expected-note {{previous declaration}} expected-note 2 {{not viable}}
+float& cv(const A*); // expected-error {{cannot be overloaded}}
+
+int& cv2(void*); // expected-note 2 {{candidate}}
+float& cv2(const void*); // expected-note 2 {{candidate}}
 
 void cv_test(A* a, B* b, const A* ac, const B* bc) {
   int &i1 = cv(a);
   int &i2 = cv(b);
-  float &f1 = cv(ac);
-  float &f2 = cv(bc);
-  int& i3 = cv2(a);
-  float& f3 = cv2(ac);
+  float &f1 = cv(ac); // expected-error {{no matching function}}
+  float &f2 = cv(bc); // expected-error {{no matching function}}
+
+  // FIXME: these should not be ambiguous
+  int& i3 = cv2(a); // expected-error {{ambiguous}}
+  float& f3 = cv2(ac); // expected-error {{ambiguous}}
 }
 
-
-int& qualid(id<P0>);
-float& qualid(id<P1>); // FIXME: GCC complains that this isn't an overload. Is it?
+// We agree with GCC that these can't be overloaded.
+int& qualid(id<P0>); // expected-note {{previous declaration}} expected-note {{not viable}}
+float& qualid(id<P1>); // expected-error {{cannot be overloaded}}
 
 void qualid_test(A *a, B *b, C *c) {
   int& i1 = qualid(a);
   int& i2 = qualid(b);
-  float& f1 = qualid(c);
+
+  // This doesn't work only because the overload was rejected above.
+  float& f1 = qualid(c); // expected-error {{no matching function}}
 
   id<P0> p1 = 0;
   p1 = 0;
@@ -91,7 +102,7 @@ objc_exception_functions_t;
 
 void (*_NSExceptionRaiser(void))(NSException *) {
     objc_exception_functions_t exc_funcs;
-    return exc_funcs.throw_exc; // expected-warning{{incompatible pointer types returning 'void (*)(NSException *)', expected 'void (*)(id)'}}
+    return exc_funcs.throw_exc; // expected-warning{{incompatible pointer types converting 'void (*)(id)' to type 'void (*)(NSException *)'}}
 }
 
 namespace test5 {
@@ -102,3 +113,13 @@ namespace test5 {
     foo(p);
   }
 }
+
+// rdar://problem/8592139
+namespace test6 {
+  void foo(id); // expected-note {{candidate}}
+  void foo(A*) __attribute__((unavailable)); // expected-note {{explicitly made unavailable}}
+
+  void test(B *b) {
+    foo(b); // expected-error {{call to unavailable function}}
+  }
+}