Backport "Handle TupleXXL in match analysis" to LTS #20791
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There's a number of problems with the match analysis of TupleXXL. Of course, they manifest as (in)exhaustivity and (un)reachability warnings. Reachability suffered by the problem that a large generic tuple scrutinee type wasn't considered extractable by the TupleXXL extractor that Typer associates the extractor pattern with. That was solved by special handling in SpaceEngine's isSubType. Exhaustivity suffered by a variety of problems, again stemming from the disconnect between the TupleXXL pattern type and the large generic tuple scrutinee (or component) type. That was solved by special handling in exhaustivityCheckable to ignore large generic tuple scrutinees. That then highlighted an irrefutable failure (checkIrrefutable), which also needed to be taught that extra large generic tuples do conform to TupleXXL extractors type, afterwhich SpaceEngine isIrrefutable needed special handling to consider TuplXXL irrefutable. [Cherry-picked e56b75e]
[Cherry-picked 5bafaac]
…19103) Previously, simpleExpr was recovered as `Literal(Constant(null))` which led to some errors in interactive. Type inference in Scala 3 works on whole chain, thus type vars were inferred as union type of `Null` because of this very reason. Recovering such errors as `unimplementedExpr` which has a type of `Nothing`, solves the issue.
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No regressions detected in the community build up to lts-19356. |
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Backports #19212 to the LTS branch.
PR submitted by the release tooling.
[skip ci]