First refactoring related to Error trees.

There are no more direct calls to context.error from Typers and Infer,
so more work needs to be done to finish it for Implicits and Namers.
I am pushing it to trunk so that all of you can share my pain (and
complain). Please do not add any more context.error randomly in that
code, instead deal with it appropriately (by creating specific error
tree).

I was trying to be as informative when it comes to error tree names
as possible, but if you feel like changing names to something more
appropriate then feel free to do so. When it comes to printing error
messages I tried to follow test suite as closily as possible but
obviously there were few changes to some tests (mostly positive, I
believe).

On my machine performance drawback was neglible but I am working on more
aggressive caching to reduce the penalty of containsError() calls even
more. Any suggestions welcome.

At the moment the code supports both styles i.e. throwing type errors
for the cases that are not yet handled and generating error trees. But
in the future we will drop the former completely (apart from cyclic
errors which can pop up almost everywhere).

Review by odersky, extempore and anyone who feels like it.

1 files changed, 15 insertions, 15 deletions

diff --git a/test/files/neg/t2641.check b/test/files/neg/t2641.check
index 2056a1b9ab..595dd46b11 100644
--- a/test/files/neg/t2641.check
+++ b/test/files/neg/t2641.check
@@ -1,24 +1,15 @@
 t2641.scala:18: error: illegal cyclic reference involving trait ManagedSeq
         with TraversableViewLike[A, ManagedSeqStrict[A], ManagedSeq[A]]
                                                          ^
-t2641.scala:16: error: illegal inheritance;
- self-type ManagedSeq does not conform to ManagedSeqStrict[A]'s selftype ManagedSeqStrict[A]
-        extends ManagedSeqStrict[A]
-                ^
-t2641.scala:17: error: illegal inheritance;
- self-type ManagedSeq does not conform to scala.collection.TraversableView[A,ManagedSeqStrict[A]]'s selftype scala.collection.TraversableView[A,ManagedSeqStrict[A]]
-        with TraversableView[A, ManagedSeqStrict[A]]
-             ^
-t2641.scala:16: error: illegal inheritance;
- self-type ManagedSeq does not conform to ScalaObject's selftype ScalaObject
-        extends ManagedSeqStrict[A]
-        ^
 t2641.scala:24: error: something is wrong (wrong class file?): trait ManagedSeq with type parameters [A,Coll] gets applied to arguments [], phase = typer
   trait Transformed[+B] extends ManagedSeq[B, Coll] with super.Transformed[B]
         ^
 t2641.scala:26: error: something is wrong (wrong class file?): trait ManagedSeq with type parameters [A,Coll] gets applied to arguments [], phase = namer
   trait Sliced extends Transformed[A] with super.Sliced {
                ^
+t2641.scala:27: error: value managedIterator is not a member of ManagedSeq
+    override def managedIterator = self.managedIterator slice (from, until)
+                                        ^
 t2641.scala:26: error: illegal inheritance; superclass Any
  is not a subclass of the superclass ManagedSeqStrict
  of the mixin trait Transformed
@@ -29,7 +20,16 @@ t2641.scala:26: error: illegal inheritance; superclass Any
  of the mixin trait Sliced
   trait Sliced extends Transformed[A] with super.Sliced {
                                                  ^
-t2641.scala:27: error: value managedIterator is not a member of ManagedSeq
-    override def managedIterator = self.managedIterator slice (from, until)
-                                        ^
+t2641.scala:16: error: illegal inheritance;
+ self-type ManagedSeq does not conform to ManagedSeqStrict[A]'s selftype ManagedSeqStrict[A]
+        extends ManagedSeqStrict[A]
+                ^
+t2641.scala:17: error: illegal inheritance;
+ self-type ManagedSeq does not conform to scala.collection.TraversableView[A,ManagedSeqStrict[A]]'s selftype scala.collection.TraversableView[A,ManagedSeqStrict[A]]
+        with TraversableView[A, ManagedSeqStrict[A]]
+             ^
+t2641.scala:16: error: illegal inheritance;
+ self-type ManagedSeq does not conform to ScalaObject's selftype ScalaObject
+        extends ManagedSeqStrict[A]
+        ^
 9 errors found