From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Wed, 16 Oct 2013 16:21:04 +0000 (+0000)
Subject: Sema: Simplify the check if a method returns an instance of the class.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a32966fd8474e7a7002f65d32ace6b7e18dee66b;p=clang

Sema: Simplify the check if a method returns an instance of the class.

Just checking if the parent of the method is the same as the return type
should be sufficient. Also fixes PR17587.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@192802 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index daf135a06e..c6537637a5 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -6911,7 +6911,9 @@ Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   if (!NewFD->isInvalidDecl() && !NewFD->hasAttr<WarnUnusedResultAttr>() &&
       Ret && Ret->hasAttr<WarnUnusedResultAttr>()) {
     const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
-    if (!(MD && MD->getCorrespondingMethodInClass(Ret, true))) {
+    // Attach the attribute to the new decl. Don't apply the attribute if it
+    // returns an instance of the class (e.g. assignment operators).
+    if (!MD || MD->getParent() != Ret) {
       NewFD->addAttr(new (Context) WarnUnusedResultAttr(SourceRange(),
                                                         Context));
     }
diff --git a/test/SemaCXX/warn-unused-result.cpp b/test/SemaCXX/warn-unused-result.cpp
index b0bf61f381..581af09080 100644
--- a/test/SemaCXX/warn-unused-result.cpp
+++ b/test/SemaCXX/warn-unused-result.cpp
@@ -78,3 +78,19 @@ void lazy() {
   DoYetAnotherThing();
 }
 }
+
+namespace PR17587 {
+struct [[clang::warn_unused_result]] Status;
+
+struct Foo {
+  Status Bar();
+};
+
+struct Status {};
+
+void Bar() {
+  Foo f;
+  f.Bar(); // expected-warning {{ignoring return value}}
+};
+
+}