quo

static VALUE
numeric_quo(VALUE x, VALUE y)
{
    if (RB_TYPE_P(y, T_FLOAT)) {
        return f_fdiv(x, y);
    }

#ifdef CANON
    if (canonicalization) {
        x = rb_rational_raw1(x);
    }
    else
#endif
    {
        x = rb_convert_type(x, T_RATIONAL, "Rational", "to_r");
    }
    return rb_funcall(x, '/', 1, y);
}