MatchData#eql?

static VALUE
match_equal(VALUE match1, VALUE match2)
{
    if (match1 == match2) return Qtrue;
    if (!RB_TYPE_P(match2, T_MATCH)) return Qfalse;
    if (!RMATCH(match1)->regexp || !RMATCH(match2)->regexp) return Qfalse;
    if (!rb_str_equal(RMATCH(match1)->str, RMATCH(match2)->str)) return Qfalse;
    if (!rb_reg_equal(match_regexp(match1), match_regexp(match2))) return Qfalse;
    int num_regs = RMATCH_NREGS(match1);
    if (num_regs != RMATCH_NREGS(match2)) return Qfalse;
    if (memcmp(RMATCH_BEG_PTR(match1), RMATCH_BEG_PTR(match2), num_regs * sizeof(OnigPosition))) return Qfalse;
    if (memcmp(RMATCH_END_PTR(match1), RMATCH_END_PTR(match2), num_regs * sizeof(OnigPosition))) return Qfalse;
    return Qtrue;
}