gcc/gcc/testsuite/gcc.dg/gomp/appendix-a/a.35.3.c

/* { dg-do compile } */

void work (int, int);

void
wrong3 (int n)
{
#pragma omp parallel default(shared)
  {
    int i;
#pragma omp for
    for (i = 0; i < n; i++)
      {
/* incorrect nesting of regions */
#pragma omp single
	work (i, 0);
      }
  }
}