error in coupon display when the coupon is 100%

It seems there is an error in the show_block_cart file.
when the coupon is 100%, the variable $taxes is calculated to 0 because the final price is 0, but not the price before the discount

($taxes = round($cart->full_total->prices[0]->price_value_with_tax - $cart->full_total->prices[0]->price_value, $this->currencyClass->getRounding($cart->full_total->prices[0]->price_currency_id))

the consequence is that the coupon is displayed without tax, when the total before the coupon is displayed with tax; so it looks like there is an error (the final price after the discount is correctly displayed at 0;

I corrected it in the file by adding a condition (in orange) in these lines
if(($taxes == 0 && $cart->coupon->discount_percent_amount_orig<100) || empty($this->options))
echo $this->currencyClass->format(@$cart->coupon->discount_value_without_tax * -1, @$cart->coupon->discount_currency_id);
else
echo $this->currencyClass->format(@$cart->coupon->discount_value * -1, @$cart->coupon->discount_currency_id);

So now for me it works; but you may have a look at your code and verfiy the error I think I detected; if I am right you may modify it; if I am wrong, you may also tell me what is my error

kind regards