Method#eql?

static VALUE
method_eq(VALUE method, VALUE other)
{
    struct METHOD *m1, *m2;
    VALUE klass1, klass2;

    if (!rb_obj_is_method(other))
        return Qfalse;
    if (CLASS_OF(method) != CLASS_OF(other))
        return Qfalse;

    Check_TypedStruct(method, &method_data_type);
    m1 = (struct METHOD *)RTYPEDDATA_GET_DATA(method);
    m2 = (struct METHOD *)RTYPEDDATA_GET_DATA(other);

    klass1 = method_entry_defined_class(m1->me);
    klass2 = method_entry_defined_class(m2->me);
    if (RB_TYPE_P(klass1, T_ICLASS)) klass1 = RBASIC_CLASS(klass1);
    if (RB_TYPE_P(klass2, T_ICLASS)) klass2 = RBASIC_CLASS(klass2);

    if (!rb_method_entry_eq(m1->me, m2->me) ||
        klass1 != klass2 ||
        m1->klass != m2->klass ||
        m1->recv != m2->recv) {
        return Qfalse;
    }

    return Qtrue;
}