1  /* { dg-do compile } */
       2  /* { dg-options "-std=c99" } */
       3  
       4  int a0;
       5  
       6  struct S
       7  {
       8      int a1;
       9      union {
      10          int a0;
      11          int a1; /* { dg-error "duplicate member" } */
      12          int a2, a3, a4, a5, a6, a7, a8, a9;
      13          int a10, a11, a12, a13, a14, a15;
      14      };
      15  };
      16  
      17  int f()
      18  {
      19      struct S s;
      20      return s.a0;
      21  }