Possibly spurious type test warning

[travisbrown]

minimized code

sealed trait Base[F[_]]
case class Foo[F[_]]() extends Base[F]
object Base

Compilation output

3 |object Base
  |       ^
  |       the type test for Foo[?] cannot be checked at runtime
// defined trait Base
// defined case class Foo
// defined object Base

expectation

Scala 2 doesn't warn here, and removing the object Base removes the warning on Dotty:

scala> sealed trait Base[F[_]]
     | case class Foo[F[_]]() extends Base[F]
// defined trait Base
// defined case class Foo

[smarter]

Fixed in 0.25 (see #9045).