dart2js: Fix hints in code base.

pkg/compiler/lib/src/js_emitter/old_emitter/nsm_emitter.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.
 
 part of dart2js.js_emitter;
 
 class NsmEmitter extends CodeEmitterHelper {
   final List<Selector> trivialNsmHandlers = <Selector>[];
 
   /// If this is true then we can generate the noSuchMethod handlers at startup
@@ skipping 133 matching lines @@
     for (int i = 0; i < trivialNsmHandlers.length; i++) {
       if (!backend.isInterceptedName(trivialNsmHandlers[i].name)) {
         firstNormalSelector = i;
         break;
       }
     }
 
     // Get the short names (JS names, perhaps minified).
     Iterable<String> shorts = trivialNsmHandlers.map((selector) =>
          namer.invocationMirrorInternalName(selector));
-    final diffShorts = <String>[];
     var diffEncoding = new StringBuffer();
 
     // Treat string as a number in base 88 with digits in ASCII order from # to
     // z.  The short name sorting is based on length, and uses ASCII order for
     // equal length strings so this means that names are ascending.  The hash
     // character, #, is never given as input, but we need it because it's the
     // implicit leading zero (otherwise we could not code names with leading
     // dollar signs).
     int fromBase88(String x) {
       int answer = 0;
@@ skipping 47 matching lines @@
         diffEncoding.write(short);
       }
       nameCounter++;
     }
 
     // Startup code that loops over the method names and puts handlers on the
     // Object class to catch noSuchMethod invocations.
     ClassElement objectClass = compiler.objectClass;
     jsAst.Expression createInvocationMirror = backend.emitter
         .staticFunctionAccess(backend.getCreateInvocationMirror());
-    var type = 0;
     if (useDiffEncoding) {
       statements.add(js.statement('''{
           var objectClassObject = processedClasses.collected[#objectClass],
               shortNames = #diffEncoding.split(","),
               nameNumber = 0,
               diffEncodedString = shortNames[0],
               calculatedShortNames = [0, 1];    // 0, 1 are args for splice.
           // If we are loading a deferred library the object class will not be in
           // the collectedClasses so objectClassObject is undefined, and we skip
           // setting up the names.
@@ skipping 85 matching lines @@
       }''', {
           'sliceOffsetParams': sliceOffsetParams,
           'noSuchMethodName': namer.noSuchMethodName,
           'createInvocationMirror': createInvocationMirror,
           'names': minify ? 'shortNames' : 'longNames',
           'sliceOffsetArguments': sliceOffsetArguments}));
 
     return statements;
   }
 }