1 files changed, 15 insertions, 3 deletions
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index eb84cff999..8ccb9b8180 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -1318,12 +1318,24 @@ static IMAKind ClassifyImplicitMemberAccess(Sema &SemaRef,
     return IMA_Error_StaticContext;
   }
 
+  CXXRecordDecl *
+        contextClass = cast<CXXMethodDecl>(DC)->getParent()->getCanonicalDecl();
+
+  // [class.mfct.non-static]p3: 
+  // ...is used in the body of a non-static member function of class X,
+  // if name lookup (3.4.1) resolves the name in the id-expression to a
+  // non-static non-type member of some class C [...]
+  // ...if C is not X or a base class of X, the class member access expression
+  // is ill-formed.
+  if (R.getNamingClass() &&
+      contextClass != R.getNamingClass()->getCanonicalDecl() &&
+      contextClass->isProvablyNotDerivedFrom(R.getNamingClass()))
+    return (hasNonInstance ? IMA_Mixed_Unrelated : IMA_Error_Unrelated);
+
   // If we can prove that the current context is unrelated to all the
   // declaring classes, it can't be an implicit member reference (in
   // which case it's an error if any of those members are selected).
-  if (IsProvablyNotDerivedFrom(SemaRef,
-                               cast<CXXMethodDecl>(DC)->getParent(),
-                               Classes))
+  if (IsProvablyNotDerivedFrom(SemaRef, contextClass, Classes))
     return (hasNonInstance ? IMA_Mixed_Unrelated : IMA_Error_Unrelated);
 
   return (hasNonInstance ? IMA_Mixed : IMA_Instance);