private types escape via bounds

[scabug]

This is in 2.9, so not recent.

private[scala] trait SpecializableCompanion
private[scala] trait AnyValCompanion extends SpecializableCompanion { }

scala> List(Byte, Char, Short)
res0: List[AnyValCompanion with ScalaObject] = List(object scala.Byte, object scala.Char, object scala.Short)

scala> var x: List[AnyValCompanion with ScalaObject] = res0
<console>:8: error: trait AnyValCompanion cannot be accessed in package scala
       var x: List[AnyValCompanion with ScalaObject] = res0
                   ^

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-4739?orig=1
Reporter: @paulp

[hrhino]

2.9 is so not recent.

[SethTisue]

same in 2.12.4:

scala> :paste -raw
package a                                                                                                               
private[a] trait T                                                                                                      
trait T1 extends T                                                                                                      
trait T2 extends T

scala> List(new a.T1 {}, new a.T2 {})
res1: List[a.T] = List($anon$1@5626d18c, $anon$2@45e9b12d)

scala> res1: List[a.T]
<console>:13: error: trait T in package a cannot be accessed in package a
       res1: List[a.T]
                    ^

but, I don't see why this would be considered a bug. what should happen instead?

[paulp]

@SethTisue Because it makes no sense to infer inaccessible types.

A: "These are Dingos."
B: "Oh, thanks, I wasn't sure what they were. Give me the first Dingo then."
A: "WHAT'S A DINGO?"

Here, it should infer List[AnyRef], not List[type-you-cannot-even-reference].