Can ことはない be used to express something other than 'you don't have to'?


I understand that ことはない is used to state that something does not have to be
done, such as:

時間は十分あるから急ぐことはない。

However, I am currently translating a survey from Japanese to English for a
friend and this phrasr is popping up often and I am not sure if I am
translating it correctly. (He is a pyscology student if that matters).

Here are a couple examples that I am struggling with:

私は道にポイ捨てしたことはない。

or

自分の失敗をもみ消したことはない。

The second seems more straight forward, 'I don't need to hide my mistakes',
but if that is the case, what is happening with the past tense of する？ Why is
it もみ消した and not もみ消す？ my understanding is that when using this ことはない grammar
point, the verb remains in dictionary form. The same applies for the second,
example, is this saying I don't need to litter? Or rather that I don't litter?
Or...I'm a bit lost?

Can anyone help me?

P.S. I apologize for any formatting errors, I am doing this on my iPad and it
does not love this website.

Thanks!




To expand on what blutorange said in the comments...

Are you familiar with the grammar pattern `～したことがある` which expresses having
the experience of having done something? For example:

> 私は日本に行ったことがある = I have been to Japan.

This is the negative, so:

> 私は道にポイ捨てしたことはない = I have never dropped litter on the street.

We're talking about past experiences so I don't think it's any wonder that the
verb is in past tense.

