Handle Typed(_: SubMatch) in PatternMatcher

[EugeneFlesselle]

Based on #25778 by @zielinsky
Fixes #25746

Strip Typed(_, _) proxies around SubMatches when computing pattern plan in PatternMatcher.

How much have you relied on LLM-based tools in this contribution?

Not at all

How was the solution tested?

Covered by existing tests from #25778

[zielinsky]

That was my first attempt and I think this change can be simplified - I don't see why we need to convert the value to a method?

Edit: Okkk now I see, sorry (It's already 6 p.m., a little late) :)
Edit2: My first attempt was only to add one case:

case Typed(t: SubMatch, _) => subMatchPlan(t)

so I didn't need to change the value to a method - but your solution looks a way better.

[EugeneFlesselle]

That was my first attempt and I think this change can be simplified

Did this approach cause issues, which led to the alternative fix?

I don't see why we need to convert the value to a method?

So the logic is applied recursively

[zielinsky]

Did this approach cause issues, which led to the alternative fix?

This fix felt like a band-aid at first. I was also not sure if just stripping the Typed there was safe, since it was put there for a reason. That's why I pushed Typed below into each case body instead.