Generalize OverridingPairs to SymbolPairs.

Increases your chance of knowing what is going on in
OverridingPairs. Introduces some new abstractions which I
hope for your own sakes you will put to use in some way:

  RelativeTo: operations relative to a prefix
  SymbolPair: two symbols being compared for something, and
    the enclosing class where the comparison is being performed

Fixed a minor bug with access by accident by way of more
principled pair analysis. See run/private-override.scala.

Upgraded the error message issued on certain conflicts
to give the line numbers of both conflicting methods, as
opposed to just one and you go hunting.

1 files changed, 5 insertions, 5 deletions

diff --git a/test/files/neg/t588.check b/test/files/neg/t588.check
index f8b5516fdc..ff08f77a6f 100644
--- a/test/files/neg/t588.check
+++ b/test/files/neg/t588.check
@@ -1,13 +1,13 @@
 t588.scala:3: error: double definition:
-method visit:(f: Int => String)Boolean and
-method visit:(f: Int => Unit)Boolean at line 2
+def visit(f: Int => Unit): Boolean at line 2 and
+def visit(f: Int => String): Boolean at line 3
 have same type after erasure: (f: Function1)Boolean
   def visit(f: Int => String): Boolean
       ^
 t588.scala:10: error: double definition:
-method f:(brac: Test.this.TypeB)Unit and
-method f:(node: Test.this.TypeA)Unit at line 9
-have same type after erasure: (brac: Test#TraitA)Unit
+def f(node: Test.this.TypeA): Unit at line 9 and
+def f(brac: Test.this.TypeB): Unit at line 10
+have same type after erasure: (node: Test#TraitA)Unit
   def f(brac : TypeB) : Unit;
       ^
 two errors found