Object#=~

static VALUE
rb_obj_match(VALUE obj1, VALUE obj2)
{
    if (rb_warning_category_enabled_p(RB_WARN_CATEGORY_DEPRECATED)) {
        rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "deprecated Object#=~ is called on %"PRIsVALUE
                "; it always returns nil", rb_obj_class(obj1));
    }
    return Qnil;
}