Fix 'Unused local variable' hints in analyzer and analysis_server.

pkg/analysis_server/test/services/search/search_engine_test.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.
 
 library test.services.src.search.search_engine;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_memory_index.dart';
@@ skipping 151 matching lines @@
   a.test(); // a-inv-r-q
   a.test = 1; // a-write-r-q
   a.test += 2; // a-read-write-r-q
   print(a.test); // a-read-r-q
   p.test(); // p-inv-ur-q
   p.test = 1; // p-write-ur-q
   p.test += 2; // p-read-write-ur-q
   print(p.test); // p-read-ur-q
 }
 ''');
-    ClassElement elementA = findElement('A');
-    ClassElement elementB = findElement('B');
     Element mainA = findElement('mainA');
     Element main = findElement('main');
     var expected = [
         _expectId(mainA, MatchKind.INVOCATION, 'test(); // a-inv-r-nq'),
         _expectId(mainA, MatchKind.WRITE, 'test = 1; // a-write-r-nq'),
         _expectId(mainA, MatchKind.READ_WRITE, 'test += 2; // a-read-write-r-nq'),
         _expectId(mainA, MatchKind.READ, 'test); // a-read-r-nq'),
         _expectIdQ(main, MatchKind.INVOCATION, 'test(); // a-inv-r-q'),
         _expectIdQ(main, MatchKind.WRITE, 'test = 1; // a-write-r-q'),
         _expectIdQ(main, MatchKind.READ_WRITE, 'test += 2; // a-read-write-r-q'),
@@ skipping 181 matching lines @@
     Element mainElement = findElement('main');
     var kind = MatchKind.REFERENCE;
     var expected = [
         _expectId(mainElement, kind, 'math.PI);', length: 'math.'.length)];
     return _verifyReferences(element, expected);
   }
 
   Future test_searchReferences_LibraryElement() {
     var codeA = 'part of lib; // A';
     var codeB = 'part of lib; // B';
-    var sourceA = addSource('/unitA.dart', codeA);
-    var sourceB = addSource('/unitB.dart', codeB);
+    addSource('/unitA.dart', codeA);
+    addSource('/unitB.dart', codeB);
     _indexTestUnit('''
 library lib;
 part 'unitA.dart';
 part 'unitB.dart';
 ''');
     LibraryElement element = testLibraryElement;
     CompilationUnitElement elementA = element.parts[0];
     CompilationUnitElement elementB = element.parts[1];
     index.indexUnit(context, elementA.node);
     index.indexUnit(context, elementB.node);
-    Element mainElement = findElement('main');
     var expected = [
         new ExpectedMatch(
             elementA,
             MatchKind.REFERENCE,
             codeA.indexOf('lib; // A'),
             'lib'.length),
         new ExpectedMatch(
             elementB,
             MatchKind.REFERENCE,
             codeB.indexOf('lib; // B'),
@@ skipping 226 matching lines @@
 
   Future test_searchTopLevelDeclarations() {
     _indexTestUnit('''
 class A {} // A
 class B = Object with A;
 typedef C();
 D() {}
 var E = null;
 class NoMatchABCDE {}
 ''');
-    NameElement element = new NameElement('test');
     Element topA = findElement('A');
     Element topB = findElement('B');
     Element topC = findElement('C');
     Element topD = findElement('D');
     Element topE = findElement('E');
-    Element topNoMatch = new MockElement('NoMatchABCDE');
     var expected = [
         _expectId(topA, MatchKind.DECLARATION, 'A {} // A'),
         _expectId(topB, MatchKind.DECLARATION, 'B ='),
         _expectId(topC, MatchKind.DECLARATION, 'C()'),
         _expectId(topD, MatchKind.DECLARATION, 'D() {}'),
         _expectId(topE, MatchKind.DECLARATION, 'E = null')];
     return _verifyTopLevelDeclarations('^[A-E]\$', expected);
   }
 
   ExpectedMatch _expectId(Element element, MatchKind kind, String search,
@@ skipping 43 matching lines @@
         pattern).then((List<SearchMatch> matches) {
       _assertMatches(matches, expectedMatches);
     });
   }
 
   static void _assertMatches(List<SearchMatch> matches,
       List<ExpectedMatch> expectedMatches) {
     expect(matches, unorderedEquals(expectedMatches));
   }
 }