llvm-gcc-4.0/gcc/testsuite/g++.old-deja/g++.pt/crash9.C

// { dg-do assemble  }

template <class T>
void f(T) {} // { dg-error "" } parameter has incomplete type

class C;    // { dg-error "" } forward declaration

void g(const C& c)
{
  f(c); // { dg-error "" } invalid use of undefined type
}