While working on Any.## I ran across some inter...

While working on Any.## I ran across some interesting tests being made
in TreeBuilder:

  val buf = new ListBuffer[(Name, Tree, Position)]
  [...]
  if (buf.iterator forall (name !=)) ...

This is always true because a Name will never equal a Tuple3. Oh
universal equality, will you never tire of toying with us? Given that
this bug has existed since r12886 one might reasonably question the
necessity of the conditionals falling prey to this, but leaving that
for another day, it should at least check what it's trying to check. No
review.

1 files changed, 27 insertions, 19 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
index 9a3760b8c6..812ad23078 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/TreeBuilder.scala
@@ -64,46 +64,54 @@ abstract class TreeBuilder {
    *  The variables keep their positions; whereas the pattern is converted to be synthetic
    *  for all nodes that contain a variable position.
    */
-  private object getvarTraverser extends Traverser {
+  class GetVarTraverser extends Traverser {
     val buf = new ListBuffer[(Name, Tree, Position)]
-    def init: Traverser = { buf.clear; this }
+
     def namePos(tree: Tree, name: Name): Position =
-      if (!tree.pos.isRange || name.toString.contains('$')) tree.pos.focus
+      if (!tree.pos.isRange || name.containsName(nme.DOLLARraw)) tree.pos.focus
       else {
         val start = tree.pos.start
         val end = start + name.decode.length
         r2p(start, start, end)
       }
+
     override def traverse(tree: Tree): Unit = {
+      def seenName(name: Name)     = buf exists (_._1 == name)
+      def add(name: Name, t: Tree) = if (!seenName(name)) buf += ((name, t, namePos(tree, name)))
       val bl = buf.length
+
       tree match {
-        case Bind(name, Typed(tree1, tpt)) =>
-          if ((name != nme.WILDCARD) && (buf.iterator forall (name !=))) {
-            buf += ((name, if (treeInfo.mayBeTypePat(tpt)) TypeTree() else tpt.duplicate, namePos(tree, name)))
-          }
+        case Bind(nme.WILDCARD, _)          =>
+          super.traverse(tree)
+
+        case Bind(name, Typed(tree1, tpt))  =>
+          val newTree = if (treeInfo.mayBeTypePat(tpt)) TypeTree() else tpt.duplicate
+          add(name, newTree)
           traverse(tree1)
-        case Bind(name, tree1) =>
-          if ((name != nme.WILDCARD) && (buf.iterator forall (name !=))) {
-            // can assume only name range as position, as otherwise might overlap
-            // with binds embedded in pattern tree1
-            buf += ((name, TypeTree(), namePos(tree, name)))
-            //println("found var "+name+" at "+namePos.show) //DEBUG
-          }
+
+        case Bind(name, tree1)              =>
+          // can assume only name range as position, as otherwise might overlap
+          // with binds embedded in pattern tree1
+          add(name, TypeTree())
           traverse(tree1)
+
         case _ =>
           super.traverse(tree)
       }
-      if (buf.length > bl) tree setPos tree.pos.makeTransparent
+      if (buf.length > bl)
+        tree setPos tree.pos.makeTransparent
+    }
+    def apply(tree: Tree) = {
+      traverse(tree)
+      buf.toList
     }
   }
 
   /** Returns list of all pattern variables, possibly with their types,
    *  without duplicates
    */
-  private def getVariables(tree: Tree): List[(Name, Tree, Position)] = {
-    getvarTraverser.init.traverse(tree)
-    getvarTraverser.buf.toList
-  }
+  private def getVariables(tree: Tree): List[(Name, Tree, Position)] =
+    new GetVarTraverser apply tree
 
   private def makeTuple(trees: List[Tree], isType: Boolean): Tree = {
     val tupString = "Tuple" + trees.length