There may be a bug in "ht-internal.h"

[AClumsyDog]

In function 'HT_GROW', there may be a bug.

    do {                                                                \
      new_len = name##_PRIMES[++prime_idx];                             \
      new_load_limit = (unsigned)(load*new_len);                        \
    } while (new_load_limit <= size &&                                  \
             prime_idx < (int)name##_N_PRIMES);    

When prime_idx grows to N_PRIMES - 1,next prime_idx becomes N_PRIMES. This is a problem with visiting PRIMES.

[azat]

Indeed, nice catch!
Can you send a PR with a patch (it will be great if you will add some regression test for this, see test/ directory for examples)?