gcc/testsuite/gcc.dg/gomp/loop-2.c

void
foo (void)
{
  int i = 0;
  #pragma omp for collapse(2)	/* { dg-error "the same loop iteration variables 'i' used in multiple associated loops" } */
  for (i = 0; i < 16; i++)
    for (i = 1; i < 32; i++)
      ;
  #pragma omp taskloop collapse(2)	/* { dg-error "the same loop iteration variables 'j' used in multiple associated loops" } */
  for (int j = 0; j < 16; j++)
    for (j = 0; j < 16; j++)
      ;
}