cps2js: Clean up some obsolete TODOs.

pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // IrNodes are kept in a separate library to have precise control over their
 // dependencies on other parts of the system.
 library dart2js.ir_nodes;
 
 import '../constants/expressions.dart';
 import '../constants/values.dart' as values show ConstantValue;
@@ skipping 436 matching lines @@
 }
 
 /// Create a potentially recursive function and store it in a [MutableVariable].
 /// The function can access itself using [GetMutableVariable] on [variable].
 /// There must not exist a [SetMutableVariable] to [variable].
 ///
 /// This can be seen as a let rec binding:
 ///
 ///   let rec [variable] = [definition] in [body]
 ///
-class DeclareFunction extends Expression implements InteriorNode {
+class DeclareFunction extends Expression
+                      implements InteriorNode, DartSpecificNode {
   final MutableVariable variable;
   final FunctionDefinition definition;
   Expression body;
 
   DeclareFunction(this.variable, this.definition);
 
   Expression plug(Expression expr) {
     assert(body == null);
     return body = expr;
   }
@@ skipping 53 matching lines @@
 
   Branch(this.condition, Continuation trueCont, Continuation falseCont)
       : trueContinuation = new Reference<Continuation>(trueCont),
         falseContinuation = new Reference<Continuation>(falseCont);
 
   accept(Visitor visitor) => visitor.visitBranch(this);
 }
 
 /// Marker interface for nodes that are only handled in the JavaScript backend.
 ///
-/// These nodes are generated by the unsugar step and need special translation
-/// to the Tree IR, which is implemented in JsTreeBuilder.
-abstract class JsSpecificNode {}
+/// These nodes are generated by the unsugar step or the [JsIrBuilder] and need
+/// special translation to the Tree IR, which is implemented in JsTreeBuilder.
+abstract class JsSpecificNode implements Node {}
+
+/// Marker interface for nodes that are only handled inthe Dart backend.
+abstract class DartSpecificNode implements Node {}
 
 /// Directly assigns to a field on a given object.
 class SetField extends Expression implements InteriorNode, JsSpecificNode {
   final Reference<Primitive> object;
   Element field;
   final Reference<Primitive> value;
   Expression body;
 
   SetField(Primitive object, this.field, Primitive value)
       : this.object = new Reference<Primitive>(object),
@@ skipping 105 matching lines @@
 class LiteralMap extends Primitive {
   final GenericType type;
   final List<LiteralMapEntry> entries;
 
   LiteralMap(this.type, this.entries);
 
   accept(Visitor visitor) => visitor.visitLiteralMap(this);
 }
 
 /// Create a non-recursive function.
-class CreateFunction extends Primitive {
+class CreateFunction extends Primitive implements DartSpecificNode {
   final FunctionDefinition definition;
 
   CreateFunction(this.definition);
 
   accept(Visitor visitor) => visitor.visitCreateFunction(this);
 }
 
 class Parameter extends Primitive {
   Parameter(Entity hint) {
     super.hint = hint;
@@ skipping 118 matching lines @@
 
   accept(Visitor visitor) => visitor.visitFunctionDefinition(this);
   applyPass(Pass pass) => pass.rewriteFunctionDefinition(this);
 
   /// Returns `true` if this function is abstract or external.
   ///
   /// If `true`, [body] is `null` and [localConstants] is empty.
   bool get isAbstract => body == null;
 }
 
-abstract class Initializer extends Node {}
+abstract class Initializer extends Node implements DartSpecificNode {}
 
 class FieldInitializer extends Initializer {
   final FieldElement element;
   final RunnableBody body;
 
   FieldInitializer(this.element, this.body);
   accept(Visitor visitor) => visitor.visitFieldInitializer(this);
 }
 
 class SuperInitializer extends Initializer {
@@ skipping 582 matching lines @@
 
   void visitIdentical(Identical node) {
     visitReference(node.left);
     visitReference(node.right);
   }
 
   void visitInterceptor(Interceptor node) {
     visitReference(node.input);
   }
 }