Fix all strong mode errors and warnings.

test/error_test.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.
 
 library error_test;
 
 import 'package:csslib/src/messages.dart';
 import 'package:test/test.dart';
 
 import 'testing.dart';
 
 /**
  * Test for unsupported font-weights values of bolder, lighter and inherit.
  */
 void testUnsupportedFontWeights() {
-  var errors = [];
+  var errors = <Message>[];
 
   // TODO(terry): Need to support bolder.
   // font-weight value bolder.
   var input = ".foobar { font-weight: bolder; }";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(errors.isEmpty, false);
   expect(errors[0].toString(), r'''
 error on line 1, column 24: Unknown property value bolder
 .foobar { font-weight: bolder; }
@@ skipping 36 matching lines @@
 .foobar {
   font-weight: inherit;
 }''');
 }
 
 /**
  * Test for unsupported line-height values of units other than px, pt and
  * inherit.
  */
 void testUnsupportedLineHeights() {
-  var errors = [];
+  var errors = <Message>[];
 
   // line-height value in percentge unit.
   var input = ".foobar { line-height: 120%; }";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(errors.isEmpty, false);
   expect(errors[0].toString(), r'''
 error on line 1, column 24: Unexpected value for line-height
 .foobar { line-height: 120%; }
                        ^^^''');
@@ skipping 31 matching lines @@
                        ^^^^^^^''');
   expect(stylesheet != null, true);
   expect(prettyPrint(stylesheet), r'''
 .foobar {
   line-height: inherit;
 }''');
 }
 
 /** Test for bad selectors. */
 void testBadSelectors() {
-  var errors = [];
+  var errors = <Message>[];
 
   // Invalid id selector.
   var input = "# foo { color: #ff00ff; }";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(errors.isEmpty, false);
   expect(errors[0].toString(), r'''
 error on line 1, column 1: Not a valid ID selector expected #id
 # foo { color: #ff00ff; }
 ^''');
@@ skipping 14 matching lines @@
 ^''');
   expect(stylesheet != null, true);
   expect(prettyPrint(stylesheet), r'''
 . foo {
   color: #f0f;
 }''');
 }
 
 /** Test for bad hex values. */
 void testBadHexValues() {
-  var errors = [];
+  var errors = <Message>[];
 
   // Invalid hex value.
   var input = ".foobar { color: #AH787; }";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(errors.isEmpty, false);
   expect(errors[0].toString(), r'''
 error on line 1, column 18: Bad hex number
 .foobar { color: #AH787; }
                  ^^^^^^''');
@@ skipping 49 matching lines @@
 
   // Formating is off with an extra space.  However, the entire value is bad
   // and isn't processed anyway.
   expect(prettyPrint(stylesheet), r'''
 .foobar {
   color: # 123 fff;
 }''');
 }
 
 void testBadUnicode() {
-  var errors = [];
+  var errors = <Message>[];
   final String input = '''
 @font-face {
   src: url(fonts/BBCBengali.ttf) format("opentype");
   unicode-range: U+400-200;
 }''';
 
   parseCss(input, errors: errors);
 
   expect(errors.isEmpty, false);
   expect(errors[0].toString(),
@@ skipping 11 matching lines @@
   parseCss(input2, errors: errors..clear());
 
   expect(errors.isEmpty, false);
   expect(errors[0].toString(),
       'error on line 3, column 20: unicode range must be less than 10FFFF\n'
       '  unicode-range: U+12FFFF;\n'
       '                   ^^^^^^');
 }
 
 void testBadNesting() {
-  var errors = [];
+  var errors = <Message>[];
 
   // Test for bad declaration in a nested rule.
   final String input = '''
 div {
   width: 20px;
   span + ul { color: blue; }
   span + ul > #aaaa {
     color: #ffghghgh;
   }
   background-color: red;
@@ skipping 72 matching lines @@
 }
 
 main() {
   test('font-weight value errors', testUnsupportedFontWeights);
   test('line-height value errors', testUnsupportedLineHeights);
   test('bad selectors', testBadSelectors);
   test('bad Hex values', testBadHexValues);
   test('bad unicode ranges', testBadUnicode);
   test('nested rules', testBadNesting);
 }