False exhaustivity for GADT under separate compilation #23817
Description
Compiler version
3.7.2
Minimized code
In file1.scala
sealed trait N[T] case class MakeTuple[T <: Tuple](v: T) extends N[T]In file2.scala
object test { def t[T](expr: N[T]): Any = expr match { case MakeTuple(_) => ??? } }Output
$ scalac file1.scala && scalac file2.scala -- [E029] Pattern Match Exhaustivity Warning: file2.scala:3:4 ------------------ 3 | expr match { | ^^^^ | match may not be exhaustive. | | It would fail on pattern case: MakeTuple(_) | | longer explanation available when compiling with `-explain` 1 warning foundBut compiling in a single scalac call e.g scalac file1.scala file2.scala gives no warnings.
Expectation
Ideally no warning should be produced. But consistently producing the warning would also be an improvement.