Selective dealiasing when printing errors.

*** Important note for busy commit log skimmers ***

Symbol method "fullName" has been trying to serve the dual role of "how
to print a symbol" and "how to find a class file." It cannot serve both
these roles simultaneously, primarily because of package objects but
other little things as well. Since in the majority of situations we want
the one which corresponds to the idealized scala world, not the grubby
bytecode, I went with that for fullName. When you require the path to a
class (e.g. you are calling Class.forName) you should use javaClassName.

  package foo { package object bar { class Bippy } }

If sym is Bippy's symbol, then

       sym.fullName == foo.bar.Bippy
  sym.javaClassName == foo.bar.package.Bippy

*** End important note ***

There are many situations where we (until now) forewent revealing
everything we knew about a type mismatch. For instance, this isn't very
helpful of scalac (at least in those more common cases where you didn't
define type X on the previous repl line.)

  scala> type X = Int
  defined type alias X

  scala> def f(x: X): Byte = x
  <console>:8: error: type mismatch;
   found   : X
   required: Byte
         def f(x: X): Byte = x
                             ^
Now it says:

   found   : X
      (which expands to)  Int
   required: Byte
         def f(x: X): Byte = x
                             ^

In addition I rearchitected a number of methods involving:

 - finding a symbol's owner
 - calculating a symbol's name
 - determining whether to print a prefix

No review.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/files/neg/override-object-no.check b/test/files/neg/override-object-no.check
index c509634b3f..6e028d0add 100644
--- a/test/files/neg/override-object-no.check
+++ b/test/files/neg/override-object-no.check
@@ -6,8 +6,8 @@ an overriding object must conform to the overridden object's class bound;
                     ^
 override-object-no.scala:21: error: overriding object Bar in trait Quux1 with object Bar in trait Quux2:
 an overriding object must conform to the overridden object's class bound;
- found   : java.lang.Object with ScalaObject{def g: java.lang.String}
- required: java.lang.Object with ScalaObject{def g: Int}
+ found   : Object with ScalaObject{def g: String}
+ required: Object with ScalaObject{def g: Int}
   trait Quux2 extends Quux1 { override object Bar { def g = "abc" } } // err
                                               ^
 override-object-no.scala:25: error: overriding object Bar in trait Quux3 of type object Quux4.this.Bar;