gcc/testsuite/g++.dg/template/error2.C

// { dg-do compile }

// Copyright (C) 2003 Free Software Foundation, Inc.
// Contributed by Nathan Sidwell 14 Aug 2003 <nathan@codesourcery.com>

// required from did not indicate the nested class

template<class T> struct X
{
  T m;	// { dg-error "incomplete type|invalid use" }
};

template<class T >
struct Derived
{
  class Nested : public X<T> // { dg-message "required" }
  {
  };
  
  Nested m; // { dg-message "required" }
  
  void Foo ();
};

void Foo (Derived<void> &x)
{
  x.Foo (); // { dg-message "required" }
}