> compile

# wipe the build output but keep the disk cache: core's next compile is an action-cache hit
$ delete target/out
> compile
$ exists target/out/jvm/scala-3.9.0/core/early/core_3-0.1.0-SNAPSHOT.jar

# an incremental round in core after the hit: app must still see core's unchanged types
$ copy-file changes/Added.scala core/Added.scala
$ copy-file changes/UseAdded.scala app/UseAdded.scala
> compile
> app/checkEarlyJar
