Fail to type generic tuple pattern match

[nicolasstucki]

tests/pending/tuple-patmat-extract.scala crashes the compiler.

It can be minimized to

val (_, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _, _) =
  (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, List(2, 1), 22, 23)

which fail with

Exception in thread "main" dotty.tools.dotc.ast.Trees$UnAssignedTypeException: type of Apply(Ident(List),List(Literal(Constant(2)), Literal(Constant(1)))) is not assigned
	at dotty.tools.dotc.ast.Trees$Tree.tpe(Trees.scala:93)
	at dotty.tools.dotc.typer.Typer.$anonfun$typedTuple$5(Typer.scala:1818)
	at scala.runtime.Tuple2Zipped$.$anonfun$map$1(Tuple2Zipped.scala:47)
	at scala.collection.immutable.List.foreach(List.scala:388)
	at scala.runtime.Tuple2Zipped$.map$extension(Tuple2Zipped.scala:45)
	at dotty.tools.dotc.typer.Typer.typedTuple(Typer.scala:1817)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1913)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1931)
	at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1962)
	at dotty.tools.dotc.reporting.trace$.apply(trace.scala:40)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1958)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1974)
	at dotty.tools.dotc.typer.Typer.$anonfun$typedAnnotated$1(Typer.scala:1712)
	at dotty.tools.dotc.util.Stats$.track(Stats.scala:37)
	at dotty.tools.dotc.typer.Typer.typedAnnotated(Typer.scala:1710)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:1910)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:1931)
	at dotty.tools.dotc.typer.Typer.$anonfun$typed$2(Typer.scala:1962)
	at dotty.tools.dotc.reporting.trace$.apply(trace.scala:40)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1958)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:1974)
	at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2037)
	at dotty.tools.dotc.typer.Typer.$anonfun$typedMatch$1(Typer.scala:973)
	at dotty.tools.dotc.util.Stats$.track(Stats.scala:37)
	at dotty.tools.dotc.typer.Typer.typedMatch(Typer.scala:967)
	...

[nicolasstucki]

Actually fails with(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, List(2, 1), 22, 23)