anchor.diff:  assert(inform_dist_counts(dist) == 10);
   inform_dist_free(dist);
   ----
  +[horizontal]
  +Header::
  +    `inform/dist.h`
   ****
   
   ****
  
positive.code: assert(inform_dist_is_valid(dist));
  inform_dist_free(dist);
  ----
  ****
  
  ****
  
negative.code: // dist->histogram ~ {142,285,333,238}
  inform_dist_free(dist);
  ----
  [horizontal]
  Header::
      `inform/dist.h`
  ****
  
  ****
  