Some minor Tree optimizations. No review.

2 files changed, 9 insertions, 12 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/Trees.scala b/src/compiler/scala/tools/nsc/ast/Trees.scala
index 7f52d40053..ecba1c23da 100644
--- a/src/compiler/scala/tools/nsc/ast/Trees.scala
+++ b/src/compiler/scala/tools/nsc/ast/Trees.scala
@@ -89,8 +89,7 @@ trait Trees extends reflect.generic.Trees { self: SymbolTable =>
 
     def equalsStructure(that : Tree) = equalsStructure0(that)(_ eq _)
     def equalsStructure0(that: Tree)(f: (Tree,Tree) => Boolean): Boolean =
-      (tree == that) || ((tree.getClass == that.getClass) && {    // XXX defining any kind of equality in terms of getClass is a mistake
-        assert(tree.productArity == that.productArity)
+      f(tree, that) || ((tree.productArity == that.productArity) && {
         def equals0(this0: Any, that0: Any): Boolean = (this0, that0) match {
           case (x: Tree, y: Tree)         => f(x, y) || (x equalsStructure0 y)(f)
           case (xs: List[_], ys: List[_]) => (xs corresponds ys)(equals0)
@@ -103,7 +102,7 @@ trait Trees extends reflect.generic.Trees { self: SymbolTable =>
             true
         }
 
-        (tree.productIterator.toList corresponds that.productIterator.toList)(equals0) && compareOriginals()
+        (tree.productIterator zip that.productIterator forall { case (x, y) => equals0(x, y) }) && compareOriginals()
       })
 
     def shallowDuplicate: Tree = new ShallowDuplicator(tree) transform tree
@@ -948,6 +947,8 @@ trait Trees extends reflect.generic.Trees { self: SymbolTable =>
 
   class TreeTypeSubstituter(val from: List[Symbol], val to: List[Type]) extends Traverser {
     val typeSubst = new SubstTypeMap(from, to)
+    def fromContains = typeSubst.fromContains
+
     override def traverse(tree: Tree) {
       if (tree.tpe ne null) tree.tpe = typeSubst(tree.tpe)
       if (tree.isDef) {
diff --git a/src/library/scala/reflect/generic/Trees.scala b/src/library/scala/reflect/generic/Trees.scala
index 2573b6b191..6493c4f667 100755
--- a/src/library/scala/reflect/generic/Trees.scala
+++ b/src/library/scala/reflect/generic/Trees.scala
@@ -104,10 +104,10 @@ trait Trees { self: Universe =>
      */
     def children: List[Tree] = {
       def subtrees(x: Any): List[Tree] = x match {
-        case EmptyTree => List()
-        case t: Tree => List(t)
+        case EmptyTree   => Nil
+        case t: Tree     => List(t)
         case xs: List[_] => xs flatMap subtrees
-        case _ => List()
+        case _           => Nil
       }
       productIterator.toList flatMap subtrees
     }
@@ -135,12 +135,8 @@ trait Trees { self: Universe =>
       buffer.toString
     }
 
-    override def hashCode(): Int = super.hashCode()
-
-    override def equals(that: Any): Boolean = that match {
-      case t: Tree => this eq t
-      case _ => false
-    }
+    final override def hashCode(): Int = System.identityHashCode(this)
+    final override def equals(that: Any) = this eq that.asInstanceOf[AnyRef]
   }
 
   private[scala] def duplicateTree(tree: Tree): Tree = tree