Fix errors and warnings

pkg/analyzer/test/src/task/dart_test.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.
 
 library analyzer.test.src.task.dart_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
@@ skipping 858 matching lines @@
       '/partB.dart': '''
 part of my_lib;
 '''
     });
     if (context.analysisOptions.enableUriInPartOf) {
       // TODO(28522)
       // Should report that names are wrong.
     } else {
       _assertErrorsWithCodes(
           [ResolverErrorCode.MISSING_LIBRARY_DIRECTIVE_WITH_PART]);
-      AnalysisError error = errorListener.errors[0];
     }
   }
 
   test_perform_error_missingLibraryDirectiveWithPart_noCommon() {
     _performBuildTask({
       '/lib.dart': '''
 part 'partA.dart';
 part 'partB.dart';
 ''',
       '/partA.dart': '''
 part of libA;
         ''',
       '/partB.dart': '''
 part of libB;
 '''
     });
     if (context.analysisOptions.enableUriInPartOf) {
       // TODO(28522)
       // Should report that names are wrong.
     } else {
       _assertErrorsWithCodes(
           [ResolverErrorCode.MISSING_LIBRARY_DIRECTIVE_WITH_PART]);
-      AnalysisError error = errorListener.errors[0];
     }
   }
 
   test_perform_error_partDoesNotExist() {
     _performBuildTask({
       '/lib.dart': '''
 library lib;
 part 'part.dart';
 '''
     });
@@ skipping 4834 matching lines @@
   /**
    * Fill [errorListener] with [result] errors in the current [task].
    */
   void _fillErrorListener(ResultDescriptor<List<AnalysisError>> result) {
     List<AnalysisError> errors = task.outputs[result] as List<AnalysisError>;
     expect(errors, isNotNull, reason: result.name);
     errorListener = new GatheringErrorListener();
     errorListener.addAll(errors);
   }
 }