inconsistent printing of types

[scabug]

In my opinion some types have an inconsistent implementation of toString. Some types return only their short names. scala.Product for example returns "Product" instead of "scala.Product".

scala> u.typeOf[scala.Product] 
res31: reflect.runtime.universe.Type = Product // wrong? 

scala> u.typeOf[java.lang.Object] 
res32: reflect.runtime.universe.Type = Object  // wrong? 

scala> u.typeOf[scala.Function1[_,_]] 
res33: reflect.runtime.universe.Type = scala.Function1[_, _] // correct? 

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-5941?orig=1
Reporter: @xeno-by
Affected Versions: 2.10.0

[scabug]

@xeno-by said:
http://groups.google.com/group/scala-user/browse_thread/thread/88e89d154e79826d

[scabug]

@xeno-by said:
The problem is actually not as minor as it looks. This happens because sometimes we get ScalaPackage from the root mirror and it gets stripped off when printing, and sometimes we get ScalaPackage from a child mirror. This begs for additional investigation.

[scabug]

@retronym said:
Linking this to a code comment:

    // Modules whose members are in the default namespace
    // SI-5941: ScalaPackage and JavaLangPackage are never ever shared between mirrors
    // as a result, `Int` becomes `scala.Int` and `String` becomes `java.lang.String`
    // I could just change `isOmittablePrefix`, but there's more to it, so I'm leaving this as a todo for now
    lazy val UnqualifiedModules = List(PredefModule, ScalaPackage, JavaLangPackage)
    // Those modules and their module classes
    lazy val UnqualifiedOwners  = UnqualifiedModules.toSet ++ UnqualifiedModules.map(_.moduleClass)

And a design doc on reflection:

https://docs.google.com/document/d/1nAwSw4TmMplsIlzh2shYLUJ5mVh3wndDa1Zm1H6an9A/edit#

And a related report from the mailing lists:

https://groups.google.com/forum/#!msg/scala-language/6TyLTfk4E-I/sg33aLe_-40J

On Wed, May 1, 2013 at 7:59 AM, Ryan Hendrickson <Ryan[email protected]> wrote:
Any ideas as to why?

Classloaders, somehow. I get the same ## result with "scala" but different results with "scala -nobootcp".

% scala210_1 -nobootcp
Welcome to Scala version 2.10.1 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_45).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import reflect.runtime.universe._
import reflect.runtime.universe._

scala>  (typeOf[String].normalize.##, typeOf[java.lang.String].normalize.##)
res0: (Int, Int) = (1712057924,559543568)

[scabug]

@xeno-by said:
Also see #6079

[retronym]

WIP: https://github.com/scala/scala/compare/2.13.x...retronym:ticket/5941?expand=1

This blocks scala/scala-partest#75, so I'm going to try to get a fix into 2.13