diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -4590,15 +4590,6 @@
   return ImplicitConversionSequence::Indistinguishable;
 }
 
-/// Determine whether the given type is valid, e.g., it is not an invalid
-/// C++ class.
-static bool isTypeValid(QualType T) {
-  if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
-    return !Record->isInvalidDecl();
-
-  return true;
-}
-
 static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
   if (!T.getQualifiers().hasUnaligned())
     return T;
@@ -4648,7 +4639,6 @@
   if (UnqualT1 == UnqualT2) {
     // Nothing to do.
   } else if (isCompleteType(Loc, OrigT2) &&
-             isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
              IsDerivedFrom(Loc, UnqualT2, UnqualT1))
     Conv |= ReferenceConversions::DerivedToBase;
   else if (UnqualT1->isObjCObjectOrInterfaceType() &&