report unused-value warning also for warn_unused types



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186793 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 8473c09..5c1a27d 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -2075,8 +2075,17 @@
     return false;
 
   case CXXTemporaryObjectExprClass:
-  case CXXConstructExprClass:
+  case CXXConstructExprClass: {
+    if (const CXXRecordDecl *Type = getType()->getAsCXXRecordDecl()) {
+      if (Type->hasAttr<WarnUnusedAttr>()) {
+        WarnE = this;
+        Loc = getLocStart();
+        R1 = getSourceRange();
+        return true;
+      }
+    }
     return false;
+  }
 
   case ObjCMessageExprClass: {
     const ObjCMessageExpr *ME = cast<ObjCMessageExpr>(this);