Optimiser disagrees with compiler over what syntax is valid

[scabug]

---

import java.io.{File}
abstract sealed trait Path {
val path: String
val name: String
}
case class ExternalPath(path: String) extends File(path) with Path {
override lazy val name: String = getName
}

$ scalac -version
Scala compiler version 2.10.0.dev-1302-g6a33a20 -- Copyright 2002-2011, LAMP/EPFL

$ scala z.scala
$

$ scala -optimize z.scala
/tmp/z.scala:6: error: overriding value path in trait Path of type String;
variable path in class File of type String has weaker access privileges; it should not be private
case class ExternalPath(path: String) extends File(path) with Path {
^
one error found
$

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-5322?orig=1
Reporter: Alan Burlison (alanbur)
Affected Versions: 2.10.0

[scabug]

@paulp said:
This is another case of java private fields polluting subclasses. (It's specific to the use of "path", which is a File private.)

See also #3160, #4762, and some others I can't find.

[scabug]

@richdougherty said:
I see this error when compiling Akka with -optimize (which we don't usually do).

[error] /p/akka/g/akka-actor/src/main/scala/akka/dispatch/Mailbox.scala:540: overriding method queue in trait QueueBasedMessageQueue of type => java.util.Queue[akka.dispatch.Envelope];
[error]  variable queue in class PriorityBlockingQueue of type Array[Object] has weaker access privileges; it should not be private
[error]     new PriorityBlockingQueue[Envelope](initialCapacity, cmp) with QueueBasedMessageQueue with UnboundedMessageQueueSemantics {
[error]         ^
[warn] 6 warnings found
[error] one error found

[scabug]

@magarciaEPFL said:
The new optimizer , http://magarciaepfl.github.io/scala/ , isn't prone to this bug. Just checked.

[SethTisue]

someone want to check if this is still a bug in 2.12? closing on the suspicion it probably isn't

[martijnhoekstra]

Confirmed can't reproduce