hash.c:269
static VALUE
rb_hash_rehash(hash)
    VALUE hash;
{
    st_table *tbl;

    rb_hash_modify(hash);
    tbl = st_init_table_with_size(&objhash, RHASH(hash)->tbl->num_entries);
    st_foreach(RHASH(hash)->tbl, rb_hash_rehash_i, (st_data_t)tbl);
    st_free_table(RHASH(hash)->tbl);
    RHASH(hash)->tbl = tbl;

    return hash;
}
