dart2js: Fix hints in code base.

pkg/compiler/lib/src/resolution/signatures.dart

 // Copyright (c) 2014, 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.
 
 part of resolution;
 
 /**
  * [SignatureResolver] resolves function signatures.
  */
 class SignatureResolver extends MappingVisitor<FormalElementX> {
@@ skipping 61 matching lines @@
     currentDefinitions = node;
     FormalElementX element = definition.accept(this);
     if (currentDefinitions.metadata != null) {
       element.metadata = compiler.resolver.resolveMetadata(element, node);
     }
     currentDefinitions = null;
     return element;
   }
 
   void validateName(Identifier node) {
-    String name = node.source;
     if (isOptionalParameter &&
         optionalParametersAreNamed &&
         isPrivateName(node.source)) {
       compiler.reportError(node, MessageKind.PRIVATE_NAMED_PARAMETER);
     }
   }
 
   void computeParameterType(FormalElementX element,
                             [VariableElement fieldElement]) {
     void computeFunctionType(FunctionExpression functionExpression) {
@@ skipping 310 matching lines @@
 
   DartType resolveReturnType(TypeAnnotation annotation) {
     if (annotation == null) return const DynamicType();
     DartType result = resolver.resolveTypeAnnotation(annotation);
     if (result == null) {
       return const DynamicType();
     }
     return result;
   }
 }