type inference does not respect access boundaries

[scabug]

abstract class A {
  private def foo = List(1, 2)
}
trait B extends A {
  private def foo = List("a", "b")
  // However it compiles correctly if the type is given:
  // private def foo: List[String] = List("a", "b")
}

% scalac29 -version
Scala compiler version 2.9.0.r23832-b20101223012507 -- Copyright 2002-2010, LAMP/EPFL
% scalac29 bug.scala
bug.scala:5: error: type mismatch;
 found   : java.lang.String("a")
 required: Int
  private def foo = List("a", "b")
                         ^
bug.scala:5: error: type mismatch;
 found   : java.lang.String("b")
 required: Int
  private def foo = List("a", "b")
                              ^
two errors found

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-4114?orig=1
Reporter: @paulp

[scabug]

@paulp said:
I've just noticed #2441 is a duplicate of this, so I'm closing that and keeping this one - but that one is worth checking out as well. The situation there looks to be specific to companions, and is along the lines of:

class T
trait A { def f: T }
object Bob {
  private class X extends T
}
class Bob extends A {
  def f = new Bob.X
}  

That should either fail to compile, or the type inferred for f in Bob should be T. Instead it is Bob.X.

[scabug]

@odersky said:
(In r23935) Closes #4114. No review.

[scabug]

@paulp said:
(In r23958) A test case for recently fixed #4114. Plus!

I had closed #2441 as a duplicate of that, but unfortunately #4114 did
not bring #2441 along with it. Then I realized I'm a programmer, not a
helpless trac watcher. As is often the case with thes things, fixing that
revealed a bug in the library. Closes #2441 for real, review by odersky.