CaseOfCase kind mismatch error fix

[Unisay]

Closes #5922 by fixing order of type arguments as they are extracted.

[effectfully]

That's not nearly enough:

• most importantly, this function is in some general module, how can you be sure you're not breaking something else by reversing the order of the result? There's no comment on what that function is supposed to return, no examples etc, maybe that's how it's supposed to work for some other use case that isn't case-of-case. I don't see any way around going through all transitive dependencies and ensuring you aren't breaking things elsewhere
• please document the offending function, so that it's clear what it returns to reduce the possibility of us screwing things up the same way again
• please add the test that caught the bug as a unit/golden test to make sure we never regress back

[Unisay]

most importantly, this function is in some general module, how can you be sure you're not breaking something else by reversing the order of the result?
I don't see any way around going through all transitive dependencies and ensuring you aren't breaking things elsewhere

Besides CaseOfCase transform I found only one place where this function extractTyArgs is used - in the PlutusIR.Analysis.Builtins.defaultUniMatcherLike and that one is only used in the CaseOfCase.

The tests for CaseOfCase transformation are all green so this gives me the confidence.

There's no comment on what that function is supposed to return, no examples etc, maybe that's how it's supposed to work for some other use case that isn't case-of-case.

I've added comment and test cases to explain the semantics as I understood them. I'd be grateful to @michaelpj for checking those test cases making sure that I inferred the intended behavior correctly.

please document the offending function, so that it's clear what it returns to reduce the possibility of us screwing things up the same way again

Done.

please add the test that caught the bug as a unit/golden test to make sure we never regress back

It was the property test that caught the bug, and its already there. I think that unit tests for the extractTyApp are enough to make sure we never have this bug again.

[michaelpj]

So the analysis is that this would only happen when we had case-of-case on a type that had two type parameters, is that right? That does indeed seem like something we might not have tripped up on until now. Hooray for the generators!

[effectfully]

As we discussed on the call I'd prefer to record the offender to increase coverage, but I'm not gonna be an ass about it, so here's your approval.

[Unisay]

As we discussed on the call I'd prefer to record the offender to increase coverage, but I'm not gonna be an ass about it, so here's your approval.

I have recorded the offender as a golden test ;-)