Fix errored return value in CheckFunctionReturnType and add a fixit hint

As discovered by ChenWJ and listed on cfe-dev, the error for Objective C 
return type ended up being wrong. This fixes that. Additionally, as a 
"while we're there", the other usages of this error and the usage of the 
FP above both use a FixItHint, so I'll add it here.

Differential Revision: https://reviews.llvm.org/D32759


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302720 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaType.cpp

@@ -2285,8 +2285,9 @@ bool Sema::CheckFunctionReturnType(QualType T, SourceLocation Loc) {
   // Methods cannot return interface types. All ObjC objects are
   // passed by reference.
   if (T->isObjCObjectType()) {
-    Diag(Loc, diag::err_object_cannot_be_passed_returned_by_value) << 0 << T;
-    return 0;
+    Diag(Loc, diag::err_object_cannot_be_passed_returned_by_value)
+        << 0 << T << FixItHint::CreateInsertion(Loc, "*");
+    return true;
   }
 
   return false;

test/SemaObjC/method-bad-param.m

@@ -20,6 +20,12 @@
 }
 @end
 
+// Ensure that this function is properly marked as a failure.
+void func_with_bad_call(bar* b, foo* f) {
+  [b cccccc:5]; // expected-warning {{instance method '-cccccc:' not found}}
+                // expected-note@-17 {{receiver is instance of class declared here}}
+}
+
 void somefunc(foo x) {} // expected-error {{interface type 'foo' cannot be passed by value; did you forget * in 'foo'}}
 foo somefunc2() {} // expected-error {{interface type 'foo' cannot be returned by value; did you forget * in 'foo'}}
 

test/SemaObjCXX/interface-return-type.mm

@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 %s -verify
+
+@class NSObject;
+template<typename T> struct C {
+      static T f(); // expected-error {{interface type 'NSObject' cannot be returned by value; did you forget * in 'NSObject'?}}
+};
+int g() { NSObject *x = C<NSObject>::f(); }//expected-error {{no member named 'f' in 'C<NSObject>'}} expected-note {{in instantiation of template class 'C<NSObject>' requested here}}