Better errors for Any/AnyRef issues.

When an error occurs because some type does not conform
to AnyRef (and an AnyRef-derived type would have sufficed)
try to say something useful about the situation.

This commit also initializes scope members before printing
error messages because the + version seems more useful than
the - version (taken from one of the checkfile diffs.)

-  def <init>: <?>
-  def methodIntIntInt: <?>
+  def <init>(): X
+  def methodIntIntInt(x: scala.Int,y: scala.Int): scala.Int

1 files changed, 3 insertions, 4 deletions

diff --git a/test/files/neg/not-possible-cause.check b/test/files/neg/not-possible-cause.check
index 9111cd0d3d..5c09fa1545 100644
--- a/test/files/neg/not-possible-cause.check
+++ b/test/files/neg/not-possible-cause.check
@@ -1,10 +1,9 @@
 not-possible-cause.scala:2: error: type mismatch;
  found   : a.type (with underlying type A)
  required: AnyRef
-Note that implicit conversions are not applicable because they are ambiguous:
- both method any2stringfmt in object Predef of type (x: Any)scala.runtime.StringFormat
- and method any2stringadd in object Predef of type (x: Any)scala.runtime.StringAdd
- are possible conversion functions from a.type to AnyRef
+Note that A is bounded only by Equals, which means AnyRef is not a known parent.
+Such types can participate in value classes, but instances
+cannot appear in singleton types or in reference comparisons.
   def foo[A <: Product](a: A) { type X = a.type }
                                          ^
 one error found