gcc/testsuite/gcc.dg/redecl-25.c

/* We used to ICE in the gimplifier, PR 106560 */
/* { dg-do compile } */
/* { dg-options "-w" } */
void **a; /* { dg-note "" } */
void b() {
  void **c; 
    c = a /* { dg-error "" } */
}
a; /* { dg-error "" } */