Fix hints

pkg/analysis_server/lib/src/computer/computer_highlights.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 computer.highlights;
 
 import 'package:analysis_server/src/protocol.dart' hide Element;
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/scanner.dart';
@@ skipping 150 matching lines @@
     }
     if (element is PropertyAccessorElement) {
       element = (element as PropertyAccessorElement).variable;
     }
     // prepare type
     HighlightRegionType type;
     if (element is FieldElement) {
       Element enclosingElement = element.enclosingElement;
       if (enclosingElement is ClassElement && enclosingElement.isEnum) {
         type = HighlightRegionType.ENUM_CONSTANT;
-      } else if ((element as FieldElement).isStatic) {
+      } else if (element.isStatic) {
         type = HighlightRegionType.FIELD_STATIC;
       } else {
         type = HighlightRegionType.FIELD;
       }
     } else if (element is TopLevelVariableElement) {
       type = HighlightRegionType.TOP_LEVEL_VARIABLE;
     }
     // add region
     if (type != null) {
       return _addRegion_node(node, type);
@@ skipping 533 matching lines @@
   void _addRegions_functionBody(FunctionBody node) {
     Token keyword = node.keyword;
     if (keyword != null) {
       Token star = node.star;
       int offset = keyword.offset;
       int end = star != null ? star.end : keyword.end;
       computer._addRegion(offset, end - offset, HighlightRegionType.BUILT_IN);
     }
   }
 }