For classes that have the warn_unused_result attribute, don't apply the
attribute to the class' methods even when they return an instance of the
class (e.g. assignment operators).

llvm-svn: 167873
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f2e8404..04f66e5 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5696,7 +5696,11 @@
       RetType->getAsCXXRecordDecl() : RetType->getPointeeCXXRecordDecl();
   if (!NewFD->isInvalidDecl() && !NewFD->hasAttr<WarnUnusedResultAttr>() &&
       Ret && Ret->hasAttr<WarnUnusedResultAttr>()) {
-    NewFD->addAttr(new (Context) WarnUnusedResultAttr(SourceRange(), Context));
+    const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
+    if (!(MD && MD->getCorrespondingMethodInClass(Ret, true))) {
+      NewFD->addAttr(new (Context) WarnUnusedResultAttr(SourceRange(),
+                                                        Context));
+    }
   }
 
   if (!getLangOpts().CPlusPlus) {