I read this as:

    IF loop variable syntax had been redefined years ago
    THEN
        go.mod would not exist
        AND
        impact would have been larger

It seems from this thread that what they meant to say was:

    IF loop variables had been redefined BEFORE go.mod existed
    THEN impact would have been larger

I think they misinterpreted the word “existed” in this case. They took it as go mod would have never been made instead of go mod didn’t exist at that time.

But that's exactly what that sentence says, isn't it? Otherwise it'd been "Arguably if Go had done this years ago when go.mod did not exist, this would have had an even bigger impact" or something like this?

> But that's exactly what that sentence says, isn't it?

No?

> Otherwise it'd been "Arguably if Go had done this years ago when go.mod did not exist, this would have had an even bigger impact" or something like this?

That’s a worst take on the same sentiment? I find your version a lot clunkier. The original sets a hypothetical stage and from that its conclusion, I think it flows better.

> The original sets a hypothetical stage and from that its conclusion, I think it flows better.

The stage is "years ago", and conclusion is "go.mod would not have existed and this would have an even bigger impact". My version re-arranges the sentence so that "go.mod not existing" bit is a part of the premise, not of the conclusion.

Tense agreement in English subjunctive is hard. Especially for non-natives such as me: I do parse the original statement like that and just can't bring myself to understand it otherwise.

English native, and I parsed it the same way. The OG comment to me reads as if "go.mod never would have existed", not "go.mod didn't exist at this point in time."

Exactly, the comma is what does it, it separates the sentence into three fragments and then the 'and' joins segments two and three.

If the comma had instead been the word "when", as suggested, this would parse the other way. It still would have been a bit awkward but would make sense.

Ironically I have stopped using the word "when" in constructions like this because it confuses non-native English (esp. German) speakers who read it in the conditional rather than temporal sense.