implicitNotFound annotation is not inherited

[prolativ]

Minimized code

@annotation.implicitNotFound("There's no Foo1")
trait Foo1

@annotation.implicitNotFound("There's no Foo2")
trait Foo2

trait Bar12 extends Foo1 with Foo2

trait Bar21 extends Foo2 with Foo1

object Bar {
  implicitly[Bar12]
  implicitly[Bar21]
}

Output

no implicit argument of type Bar12 was found for parameter ev of method implicitly in object DottyPredef

no implicit argument of type Bar21 was found for parameter ev of method implicitly in object DottyPredef

Expectation

There's no Foo2

There's no Foo1

According to the comment on scala.annotation.implicitNotFound:

The annotation is effectively inherited by subtypes if they are not annotated.

In scala 2.13 this works as described. Although not explicitly documented, the order of inheritance is taken into account there and it makes sense to keep this behaviour.

[odersky]

I agree we should follow scala 2.13's behavior here.