Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -5105,6 +5105,7 @@
 
     // Cast LHS to type of use.
     QualType UseType = isIndirect ? Context.getPointerType(Class) : Class;
+    UseType = UseType.withCVRQualifiers(LHS.get()->getType().getCVRQualifiers());
     ExprValueKind VK = isIndirect ? VK_RValue : LHS.get()->getValueKind();
     LHS = ImpCastExprToType(LHS.get(), UseType, CK_DerivedToBase, VK,
                             &BasePath);
Index: test/SemaCXX/PR27037.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/PR27037.cpp
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+struct A {
+  void f();
+};
+
+struct B : A {};
+
+void m() {
+  const B b;
+  (b.*&B::f)();  // expected-error{{drops 'const' qualifier}}
+}