Type member widened to Any when passed out of inline method

[LPTK]

Minimized code

class C {
  type A
  inline def test: A = ???
}
@main def m = {
  val c = C()
  val x: c.A = c.test
}

Output

Found:    Any
Required: c.A

https://scastie.scala-lang.org/dB277yJnSs6qID8kkxvZxA

Expectation

Compiles.

[odersky]

It now works with transparent inline. It also compiles OK as given with inline, but fails at Ycheck:

*** error while checking test.scala after phase inlining ***
exception occurred while compiling test.scala
java.lang.AssertionError: assertion failed: Found:    Any
Required: c.A
found: class Any in package scala with class Any, flags = open abstract <noinits> <permanent>, underlying = Any, {...}
expected: type A in class C with type A, flags = <deferred> <touched>, underlying = c.A, , Any, {...}
tree = {
  val C_this: (c : C) = c
  ??? :C_this.A
} while compiling test.scala
Exception in thread "main" java.lang.AssertionError: assertion failed: Found:    Any
Required: c.A
found: class Any in package scala with class Any, flags = open abstract <noinits> <permanent>, underlying = Any, {...}
expected: type A in class C with type A, flags = <deferred> <touched>, underlying = c.A, , Any, {...}
tree = {
  val C_this: (c : C) = c
  ??? :C_this.A
}
	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
	at dotty.tools.dotc.transform.TreeChecker$Checker.adapt(TreeChecker.scala:598)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2960)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2964)
	at dotty.tools.dotc.transform.TreeChecker$Checker.typed(TreeChecker.scala:309)```

[odersky]

@mbovel , @nicolasstucki I assigned to you both since this is at the intersection of inlining and dependent typing.