Cyclic Error with separate compilation

[michelou]

Minimized code

Given the following two Scala source files (located in separate directories) :

// src\main\scala\Main.scala
object JSON {
  sealed trait Json
  final case class JArray(elems: JValue*) extends Json
  type JValue = Number | JArray
}

object Main extends App {
  println(JSON.JArray(1))
}

// src\test\scala\MainTest.scala
object MainTest extends App {
  println(JSON.JArray(1))
}

Output

Compilation (and execution) of Main.scala works as expected; (separate) compilation of MainTest.scala fails.

$ dotc -version
Dotty compiler version 0.26.0-bin-20200710-a162b7b-NIGHTLY-git-a162b7b -- Copyright 2002-2020, LAMP/EPFL

$ mkdir target\classes target\test-classes

$ dotc -d target\classes src\main\scala\Main.scala

$ dotr -cp target\classes Main
JArray(ArraySeq(1))

$ dotc -classpath target\classes -d target\test-classes src\test\scala\MainTest.scala
-- [E046] Cyclic Error: src\test\scala\MainTest.scala:2:15 ---------------------
2 |  println(JSON.JArray(1))
  |               ^
  |               Cyclic reference involving trait Seq

longer explanation available when compiling with `-explain`
1 error found

NB. Java SDK is jdk-1.8.0_252-b09. The same error occurs with previous versions of Dotty (e.g. 0.25.0-RC2 or 0.24.0-RC1).

Expectation

Separate compilation succeeds (and Main and MainTest print the same result).

[griggt]

This seems to have been fixed by #9618.

[michelou]

Confirmed.