support the warn_unused_result in C++ class methods

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@92095 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/warn-unused-variables.cpp b/test/SemaCXX/warn-unused-variables.cpp
index 83a61bf..5620248 100644
--- a/test/SemaCXX/warn-unused-variables.cpp
+++ b/test/SemaCXX/warn-unused-variables.cpp
@@ -32,3 +32,14 @@
     C();
   }
 }
+
+
+struct X {
+ int foo() __attribute__((warn_unused_result));
+};
+
+void bah() {
+  X x, *x2;
+  x.foo(); // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
+  x2->foo(); // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
+}