All strong mode cleaning of dart2js.

pkg/compiler/lib/src/constants/constant_constructors.dart

 // Copyright (c) 2015, 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.
 
 // TODO(johnniwinther): Remove this library when all constant constructors are
 // computed during resolution.
 library dart2js.constants.constant_constructors;
 
 import '../common.dart';
 import '../elements/elements.dart';
@@ skipping 54 matching lines @@
 
   visitNode(Node node) {
     internalError(node, 'Unhandled node $node: ${node.toDebugString()}');
   }
 
   @override
   bulkHandleNode(Node node, String template, _) {
     internalError(node, template.replaceFirst('#', '$node'));
   }
 
-  internalError(Node node, String message) {
+  internalError(Spannable node, String message) {
     throw new UnsupportedError(message);
   }
 
   ConstantConstructor visitGenerativeConstructorDeclaration(
       FunctionExpression node,
       ConstructorElement constructor,
       NodeList parameters,
       NodeList initializers,
       Node body,
       _) {
@@ skipping 270 matching lines @@
   ConstantExpression visitNamedArgument(NamedArgument node) {
     return apply(node.expression);
   }
 
   @override
   ConstantExpression visitIfNull(Send node, Node left, Node right, _) {
     return new BinaryConstantExpression(
         apply(left), BinaryOperator.IF_NULL, apply(right));
   }
 }