Imported From: https://issues.scala-lang.org/browse/SI-4991?orig=1
Reporter: ngukho
See #5031

@som-snytt said:
Same example {foo => t4991}. One source file.

Under separate compilation of a client using 2.10, scalac emits the same class file error; but compiling together works.

# footnote, 2.9.1 is unhappy compiling pkg obj after 2.10 without cleaning
$ scalac t4991.scala
??? base trait ScalaObject not found in basetypes of object t4991

# 2.10
$ spala
Welcome to Scala version 2.10.0-20120501-234146-b27abca41a (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_22).
Type in expressions to have them evaluated.
Type :help for more information.

scala> t4991.Foo.bar
error: error while loading Foo, class file '.\t4991\Foo.class' contains wrong class Int

scala> import t4991._
import t4991._

scala> import Foo._
<console>:10: error: erroneous or inaccessible type
       import Foo._
              ^

@paulp said:
We need a determination on what's supposed to happen when there is a type alias with a name which would be an object's companion class if it had one. Right now there are a bunch of ways for it to fail, because none of the code which hops between related classes was written to take this into account. It is made yet buggier by the fact that the type alias and object have different owners (the package object class and the package class.)

@adriaanm said (edited on May 8, 2012 3:20:57 PM UTC):
Martin: only classes can be companions, type alias should not be considered
top-level type aliased (in package objects) conflict with the top-level class that's created speculatively before parsing a class file

synonymous class and type alias in the same scope is not allowed -- can we delay creating the class symbol without knowing we need to?

object and type alias should be allowed to co-exist (however, class and type alias is not allowed)

Duplicate was fixed.