Is this sentence “If/let's say we found it, what would we have done?” grammatically correct?

Question

1. "If we found it, what would we have done?"

2. "Let's say we found it, what would we have done?"

I don't think they are not grammatically correct, because we didn't find it. For this reason, the sentence should express a hypothetical situation. So, they should be rewritten as in

3. "If we had found it, what would we have done?"

4. "Let's say we had found it, what would we have done?"

But interestingly, after giving a survey on whether they sound natural or not, I have got a lot of votes from native speakers that they sound natural.

I guess they wouldn't regard "if we found it" or "let's say we found it" as a hypothetical situation of the past, but the real situation of the past.

I want to hear your opinions on it.

Answer 1

I guess they wouldn't regard "if we found it" or "let's say we found it" as a hypothetical situation of the past, but the real situation of the past.

I can't speak for all native speakers, of course, but I think you're overanalyzing it.

If you ask native speakers with a good command of grammar: Which of these sounds more correct to you?

• "If we found it, what would we have done?"

• "If we had found it, what would we have done?"

I think most would pick the second sentence. However, if you ask: Does this sound grammatically correct?

• "If we found it, what would we have done?"

I think many would say yes, mostly because they aren't thinking it through as thoroughly as you are. For one, in conversation, we just talk and listen; we don't pay much mind to grammatical complexities such as epistemic modality. For another, the sentence is understandable enough as-is, and the grammatical faux pas you're highlighting in your question wouldn't be terribly jarring to many native speakers. Perhaps this is partly due to the sentence's phonetic resemblance to the contracted version:

• "If we'd found it, what would we have done?

In short, native speakers wouldn't argue that this is a "real situation of the past," but they simply wouldn't notice the error. On the other hand, I think a misconjugated verb would be more evident to most native speakers:

• If we finds it, what will we do?

Answer 2

It can express a perfect aspect in the conditional mood referring to the future. "Let's say (for example), we found it (tomorrow), what would we have done (with it by the end of the week)?