1  /* { dg-do compile } */
       2  /* { dg-options "-Wsign-compare -std=c99" } */
       3  
       4  #include <stdbool.h>
       5  
       6  int foo()
       7  {
       8    unsigned char b = '1';
       9  
      10    bool x = ~b; /* { dg-warning "promoted bitwise complement of an unsigned value is always nonzero" } */
      11  
      12    return 0;
      13  }