Don't check use of a member function declaration used if the member function is virtual and the member reference expression doesn't explicitly qualify it. Fixes PR4878.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81460 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 26 insertions, 1 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 723d6d7dfa..53f3dde283 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -2142,8 +2142,16 @@ Sema::BuildMemberReferenceExpr(Scope *S, ExprArg Base, SourceLocation OpLoc,
     if (MemberDecl->isInvalidDecl())
       return ExprError();
 
+    bool ShouldCheckUse = true;
+    if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(MemberDecl)) {
+      // Don't diagnose the use of a virtual member function unless it's
+      // explicitly qualified.
+      if (MD->isVirtual() && (!SS || !SS->isSet()))
+        ShouldCheckUse = false;
+    }
+    
     // Check the use of this field
-    if (DiagnoseUseOfDecl(MemberDecl, MemberLoc))
+    if (ShouldCheckUse && DiagnoseUseOfDecl(MemberDecl, MemberLoc))
       return ExprError();
 
     if (FieldDecl *FD = dyn_cast<FieldDecl>(MemberDecl)) {
diff --git a/test/SemaCXX/attr-deprecated.cpp b/test/SemaCXX/attr-deprecated.cpp
index 99a249e10d..10b4a55198 100644
--- a/test/SemaCXX/attr-deprecated.cpp
+++ b/test/SemaCXX/attr-deprecated.cpp
@@ -24,3 +24,20 @@ void A::h(A* a)
   (void)b;
   (void)a->b;
 }
+
+struct B {
+  virtual void f() __attribute__((deprecated));
+};
+
+struct C : B {
+  virtual void f();
+};
+
+void f(B* b, C *c) {
+  b->f();
+  b->B::f(); // expected-warning{{'f' is deprecated}}
+  
+  c->f();
+  c->C::f();
+  c->B::f(); // expected-warning{{'f' is deprecated}}
+}