Remove unneeded use of Tree#id

Author: phaller

src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala

@@ -138,38 +138,38 @@ trait CPSUtils {
   }
 
   def isTailReturn(retExpr: Tree, body: Tree): Boolean = {
-    val removedIds = ListBuffer[Int]()
-    removeTailReturn(body, removedIds)
-    removedIds contains retExpr.id
+    val removed = ListBuffer[Tree]()
+    removeTailReturn(body, removed)
+    removed contains retExpr
   }
 
-  def removeTailReturn(tree: Tree, ids: ListBuffer[Int]): Tree = tree match {
+  def removeTailReturn(tree: Tree, removed: ListBuffer[Tree]): Tree = tree match {
     case Block(stms, r @ Return(expr)) =>
-      ids += r.id
+      removed += r
       treeCopy.Block(tree, stms, expr)
 
     case Block(stms, expr) =>
-      treeCopy.Block(tree, stms, removeTailReturn(expr, ids))
+      treeCopy.Block(tree, stms, removeTailReturn(expr, removed))
 
     case If(cond, r1 @ Return(thenExpr), r2 @ Return(elseExpr)) =>
-      ids ++= Seq(r1.id, r2.id)
-      treeCopy.If(tree, cond, removeTailReturn(thenExpr, ids), removeTailReturn(elseExpr, ids))
+      removed ++= Seq(r1, r2)
+      treeCopy.If(tree, cond, removeTailReturn(thenExpr, removed), removeTailReturn(elseExpr, removed))
 
     case If(cond, thenExpr, elseExpr) =>
-      treeCopy.If(tree, cond, removeTailReturn(thenExpr, ids), removeTailReturn(elseExpr, ids))
+      treeCopy.If(tree, cond, removeTailReturn(thenExpr, removed), removeTailReturn(elseExpr, removed))
 
     case Try(block, catches, finalizer) =>
       treeCopy.Try(tree,
-        removeTailReturn(block, ids),
-        (catches map (t => removeTailReturn(t, ids))).asInstanceOf[List[CaseDef]],
-        removeTailReturn(finalizer, ids))
+        removeTailReturn(block, removed),
+        (catches map (t => removeTailReturn(t, removed))).asInstanceOf[List[CaseDef]],
+        removeTailReturn(finalizer, removed))
 
     case CaseDef(pat, guard, r @ Return(expr)) =>
-      ids += r.id
+      removed += r
       treeCopy.CaseDef(tree, pat, guard, expr)
 
     case CaseDef(pat, guard, body) =>
-      treeCopy.CaseDef(tree, pat, guard, removeTailReturn(body, ids))
+      treeCopy.CaseDef(tree, pat, guard, removeTailReturn(body, removed))
 
     case _ =>
       tree

src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala

@@ -52,12 +52,12 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with
           debuglog("transforming " + dd.symbol)
 
           atOwner(dd.symbol) {
-            val tailReturns = ListBuffer[Int]()
+            val tailReturns = ListBuffer[Tree]()
             val rhs = removeTailReturn(rhs0, tailReturns)
             // throw an error if there is a Return tree which is not in tail position
             rhs0 foreach {
               case r @ Return(_) =>
-                if (!tailReturns.contains(r.id))
+                if (!tailReturns.contains(r))
                   unit.error(r.pos, "return expressions in CPS code must be in tail position")
               case _ => /* do nothing */
             }