gcc/gcc/testsuite/g++.dg/lookup/using7.C

template <typename T, bool=T::X> struct A
{
  int i;
};

template <typename T> struct B : A<T>
{ // { dg-error "incomplete" }
  using A<T>::i; // { dg-error "incomplete" "incomplete" } 
                 // { dg-error "using" "using" { target *-*-* } 8 }
};

B<void> b; // { dg-message "instantiated" }