Fix all strong mode errors and warnings.

test/compiler_test.dart

 // Copyright (c) 2012, 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 compiler_test;
 
 import 'dart:convert';
 import 'package:test/test.dart';
 import 'package:csslib/parser.dart';
+import 'package:csslib/src/messages.dart';
 import 'package:csslib/visitor.dart';
 import 'testing.dart';
 
 void testClass() {
-  var errors = [];
+  var errors = <Message>[];
   var input = ".foobar {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
 
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var selectorSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
   expect(selectorSeqs.length, 1);
   final simpSelector = selectorSeqs[0].simpleSelector;
   expect(simpSelector is ClassSelector, true);
   expect(selectorSeqs[0].isCombinatorNone, true);
   expect(simpSelector.name, "foobar");
 }
 
 void testClass2() {
-  var errors = [];
+  var errors = <Message>[];
   var input = ".foobar .bar .no-story {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
   expect(simpleSeqs.length, 3);
 
   var simpSelector0 = simpleSeqs[0].simpleSelector;
   expect(simpSelector0 is ClassSelector, true);
   expect(simpleSeqs[0].isCombinatorNone, true);
   expect(simpSelector0.name, "foobar");
 
   var simpSelector1 = simpleSeqs[1].simpleSelector;
   expect(simpSelector1 is ClassSelector, true);
   expect(simpleSeqs[1].isCombinatorDescendant, true);
   expect(simpSelector1.name, "bar");
 
   var simpSelector2 = simpleSeqs[2].simpleSelector;
   expect(simpSelector2 is ClassSelector, true);
   expect(simpleSeqs[2].isCombinatorDescendant, true);
   expect(simpSelector2.name, "no-story");
 }
 
 void testId() {
-  var errors = [];
+  var errors = <Message>[];
   var input = "#elemId {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 1);
   var simpSelector = simpleSeqs[0].simpleSelector;
   expect(simpSelector is IdSelector, true);
   expect(simpleSeqs[0].isCombinatorNone, true);
   expect(simpSelector.name, "elemId");
 }
 
 void testElement() {
-  var errors = [];
+  var errors = <Message>[];
   var input = "div {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 1);
 
   final simpSelector = simpleSeqs[0].simpleSelector;
   expect(simpSelector is ElementSelector, true);
   expect(simpleSeqs[0].isCombinatorNone, true);
@@ skipping 28 matching lines @@
   expect(simpleSeqs[1].isCombinatorDescendant, true);
   expect(simpSelector1.name, "div");
 
   var simpSelector2 = simpleSeqs[2].simpleSelector;
   expect(simpSelector2 is ElementSelector, true);
   expect(simpleSeqs[2].isCombinatorDescendant, true);
   expect(simpSelector2.name, "span");
 }
 
 void testNamespace() {
-  var errors = [];
+  var errors = <Message>[];
   var input = "ns1|div {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 1);
-  var simpSelector = simpleSeqs[0].simpleSelector;
-  expect(simpSelector is NamespaceSelector, true);
+  expect(simpleSeqs[0].simpleSelector is NamespaceSelector, true);
+  var simpSelector = simpleSeqs[0].simpleSelector as NamespaceSelector;
   expect(simpleSeqs[0].isCombinatorNone, true);
   expect(simpSelector.isNamespaceWildcard, false);
   expect(simpSelector.namespace, "ns1");
   var elementSelector = simpSelector.nameAsSimpleSelector;
   expect(elementSelector is ElementSelector, true);
   expect(elementSelector.isWildcard, false);
   expect(elementSelector.name, "div");
 }
 
 void testNamespace2() {
-  var errors = [];
+  var errors = <Message>[];
   var input = "ns1|div div ns2|span .foobar {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 4);
 
-  var simpSelector0 = simpleSeqs[0].simpleSelector;
-  expect(simpSelector0 is NamespaceSelector, true);
+  expect(simpleSeqs[0].simpleSelector is NamespaceSelector, true);
+  var simpSelector0 = simpleSeqs[0].simpleSelector as NamespaceSelector;
   expect(simpleSeqs[0].isCombinatorNone, true);
   expect(simpSelector0.namespace, "ns1");
   var elementSelector0 = simpSelector0.nameAsSimpleSelector;
   expect(elementSelector0 is ElementSelector, true);
   expect(elementSelector0.isWildcard, false);
   expect(elementSelector0.name, "div");
 
   var simpSelector1 = simpleSeqs[1].simpleSelector;
   expect(simpSelector1 is ElementSelector, true);
   expect(simpleSeqs[1].isCombinatorDescendant, true);
   expect(simpSelector1.name, "div");
 
-  var simpSelector2 = simpleSeqs[2].simpleSelector;
-  expect(simpSelector2 is NamespaceSelector, true);
+  expect(simpleSeqs[2].simpleSelector is NamespaceSelector, true);
+  var simpSelector2 = simpleSeqs[2].simpleSelector as NamespaceSelector;
   expect(simpleSeqs[2].isCombinatorDescendant, true);
   expect(simpSelector2.namespace, "ns2");
   var elementSelector2 = simpSelector2.nameAsSimpleSelector;
   expect(elementSelector2 is ElementSelector, true);
   expect(elementSelector2.isWildcard, false);
   expect(elementSelector2.name, "span");
 
   var simpSelector3 = simpleSeqs[3].simpleSelector;
   expect(simpSelector3 is ClassSelector, true);
   expect(simpleSeqs[3].isCombinatorDescendant, true);
   expect(simpSelector3.name, "foobar");
 }
 
 void testSelectorGroups() {
-  var errors = [];
+  var errors = <Message>[];
   var input =
       "div, .foobar ,#elemId, .xyzzy .test, ns1|div div #elemId .foobar {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 5);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var groupSelector0 = ruleset.selectorGroup.selectors[0];
   expect(groupSelector0.simpleSelectorSequences.length, 1);
   var selector0 = groupSelector0.simpleSelectorSequences[0];
   var simpleSelector0 = selector0.simpleSelector;
   expect(simpleSelector0 is ElementSelector, true);
   expect(selector0.isCombinatorNone, true);
   expect(simpleSelector0.name, "div");
@@ skipping 26 matching lines @@
   var selector31 = groupSelector3.simpleSelectorSequences[1];
   var simpleSelector31 = selector31.simpleSelector;
   expect(simpleSelector31 is ClassSelector, true);
   expect(selector31.isCombinatorDescendant, true);
   expect(simpleSelector31.name, "test");
 
   var groupSelector4 = ruleset.selectorGroup.selectors[4];
   expect(groupSelector4.simpleSelectorSequences.length, 4);
 
   var selector40 = groupSelector4.simpleSelectorSequences[0];
-  var simpleSelector40 = selector40.simpleSelector;
-  expect(simpleSelector40 is NamespaceSelector, true);
+  expect(selector40.simpleSelector is NamespaceSelector, true);
+  var simpleSelector40 = selector40.simpleSelector as NamespaceSelector;
   expect(selector40.isCombinatorNone, true);
   expect(simpleSelector40.namespace, "ns1");
   var elementSelector = simpleSelector40.nameAsSimpleSelector;
   expect(elementSelector is ElementSelector, true);
   expect(elementSelector.isWildcard, false);
   expect(elementSelector.name, "div");
 
   var selector41 = groupSelector4.simpleSelectorSequences[1];
   var simpleSelector41 = selector41.simpleSelector;
   expect(simpleSelector41 is ElementSelector, true);
   expect(selector41.isCombinatorDescendant, true);
   expect(simpleSelector41.name, "div");
 
   var selector42 = groupSelector4.simpleSelectorSequences[2];
   var simpleSelector42 = selector42.simpleSelector;
   expect(simpleSelector42 is IdSelector, true);
   expect(selector42.isCombinatorDescendant, true);
   expect(simpleSelector42.name, "elemId");
 
   var selector43 = groupSelector4.simpleSelectorSequences[3];
   var simpleSelector43 = selector43.simpleSelector;
   expect(selector43.isCombinatorDescendant, true);
   expect(simpleSelector43.name, "foobar");
 }
 
 void testCombinator() {
-  var errors = [];
+  var errors = <Message>[];
   var input = ".foobar > .bar + .no-story ~ myNs|div #elemId {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 5);
 
   var selector0 = simpleSeqs[0];
   var simpleSelector0 = selector0.simpleSelector;
   expect(simpleSelector0 is ClassSelector, true);
   expect(selector0.isCombinatorNone, true);
   expect(simpleSelector0.name, "foobar");
 
   var selector1 = simpleSeqs[1];
   var simpleSelector1 = selector1.simpleSelector;
   expect(simpleSelector1 is ClassSelector, true);
   expect(selector1.isCombinatorGreater, true);
   expect(simpleSelector1.name, "bar");
 
   var selector2 = simpleSeqs[2];
   var simpleSelector2 = selector2.simpleSelector;
   expect(simpleSelector2 is ClassSelector, true);
   expect(selector2.isCombinatorPlus, true);
   expect(simpleSelector2.name, "no-story");
 
   var selector3 = simpleSeqs[3];
-  var simpleSelector3 = selector3.simpleSelector;
-  expect(simpleSelector3 is NamespaceSelector, true);
+  expect(selector3.simpleSelector is NamespaceSelector, true);
+  var simpleSelector3 = selector3.simpleSelector as NamespaceSelector;
   expect(selector3.isCombinatorTilde, true);
   expect(simpleSelector3.namespace, "myNs");
   var elementSelector = simpleSelector3.nameAsSimpleSelector;
   expect(elementSelector is ElementSelector, true);
   expect(elementSelector.isWildcard, false);
   expect(elementSelector.name, "div");
 
   var selector4 = simpleSeqs[4];
   var simpleSelector4 = selector4.simpleSelector;
   expect(simpleSelector4 is IdSelector, true);
   expect(selector4.isCombinatorDescendant, true);
   expect(simpleSelector4.name, "elemId");
 }
 
 void testWildcard() {
-  var errors = [];
+  var errors = <Message>[];
   var input = "* {}";
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
-  var ruleset = stylesheet.topLevels[0];
+  var ruleset = stylesheet.topLevels[0] as RuleSet;
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   var simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 1);
   var simpSelector = simpleSeqs[0].simpleSelector;
   expect(simpSelector is ElementSelector, true);
   expect(simpleSeqs[0].isCombinatorNone, true);
   expect(simpSelector.isWildcard, true);
@@ skipping 11 matching lines @@
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
   ruleset = stylesheet.topLevels[0];
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 2);
 
-  var selector0 = simpleSeqs[0];
-  var simpleSelector0 = selector0.simpleSelector;
-  expect(simpleSelector0 is ElementSelector, true);
-  expect(selector0.isCombinatorNone, true);
-  expect(simpleSelector0.isWildcard, true);
-  expect(simpleSelector0.name, "*");
+  {
+    var selector0 = simpleSeqs[0];
+    var simpleSelector0 = selector0.simpleSelector;
+    expect(simpleSelector0 is ElementSelector, true);
+    expect(selector0.isCombinatorNone, true);
+    expect(simpleSelector0.isWildcard, true);
+    expect(simpleSelector0.name, "*");
+  }
 
   var selector1 = simpleSeqs[1];
   var simpleSelector1 = selector1.simpleSelector;
   expect(simpleSelector1 is ClassSelector, true);
   expect(selector1.isCombinatorNone, true);
   expect(simpleSelector1.name, "foobar");
 
   input = "myNs|*.foobar {}";
   stylesheet = parseCss(input, errors: errors..clear());
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels.length, 1);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
   ruleset = stylesheet.topLevels[0];
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 2);
 
-  selector0 = simpleSeqs[0];
-  simpleSelector0 = selector0.simpleSelector;
-  expect(simpleSelector0 is NamespaceSelector, true);
-  expect(selector0.isCombinatorNone, true);
-  expect(simpleSelector0.isNamespaceWildcard, false);
-  var elementSelector = simpleSelector0.nameAsSimpleSelector;
-  expect("myNs", simpleSelector0.namespace);
-  expect(elementSelector.isWildcard, true);
-  expect("*", elementSelector.name);
+  {
+    var selector0 = simpleSeqs[0];
+    expect(selector0.simpleSelector is NamespaceSelector, true);
+    var simpleSelector0 = selector0.simpleSelector as NamespaceSelector;
+    expect(selector0.isCombinatorNone, true);
+    expect(simpleSelector0.isNamespaceWildcard, false);
+    var elementSelector = simpleSelector0.nameAsSimpleSelector;
+    expect("myNs", simpleSelector0.namespace);
+    expect(elementSelector.isWildcard, true);
+    expect("*", elementSelector.name);
+  }
 
   selector1 = simpleSeqs[1];
   simpleSelector1 = selector1.simpleSelector;
   expect(simpleSelector1 is ClassSelector, true);
   expect(selector1.isCombinatorNone, true);
   expect("foobar", simpleSelector1.name);
 
   input = "*|*.foobar {}";
   stylesheet = parseCss(input, errors: errors..clear());
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   walkTree(stylesheet);
 
   expect(stylesheet.topLevels[0] is RuleSet, true);
   ruleset = stylesheet.topLevels[0];
   expect(ruleset.selectorGroup.selectors.length, 1);
   expect(ruleset.declarationGroup.declarations.length, 0);
 
   simpleSeqs = ruleset.selectorGroup.selectors[0].simpleSelectorSequences;
 
   expect(simpleSeqs.length, 2);
 
-  selector0 = simpleSeqs[0];
-  simpleSelector0 = selector0.simpleSelector;
-  expect(simpleSelector0 is NamespaceSelector, true);
-  expect(selector0.isCombinatorNone, true);
-  expect(simpleSelector0.isNamespaceWildcard, true);
-  expect("*", simpleSelector0.namespace);
-  elementSelector = simpleSelector0.nameAsSimpleSelector;
-  expect(elementSelector.isWildcard, true);
-  expect("*", elementSelector.name);
+  {
+    var selector0 = simpleSeqs[0];
+    expect(selector0.simpleSelector is NamespaceSelector, true);
+    var simpleSelector0 = selector0.simpleSelector as NamespaceSelector;
+    expect(selector0.isCombinatorNone, true);
+    expect(simpleSelector0.isNamespaceWildcard, true);
+    expect("*", simpleSelector0.namespace);
+    var elementSelector = simpleSelector0.nameAsSimpleSelector;
+    expect(elementSelector.isWildcard, true);
+    expect("*", elementSelector.name);
+  }
 
   selector1 = simpleSeqs[1];
   simpleSelector1 = selector1.simpleSelector;
   expect(simpleSelector1 is ClassSelector, true);
   expect(selector1.isCombinatorNone, true);
   expect("foobar", simpleSelector1.name);
 }
 
 /** Test List<int> as input to parser. */
 void testArrayOfChars() {
-  var errors = [];
+  var errors = <Message>[];
   var input = '<![CDATA[.foo { '
       'color: red; left: 20px; top: 20px; width: 100px; height:200px'
       '}'
       '#div {'
       'color : #00F578; border-color: #878787;'
       '}]]>';
 
   var stylesheet = parse(UTF8.encode(input), errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   expect(prettyPrint(stylesheet), r'''
 .foo {
   color: #f00;
   left: 20px;
   top: 20px;
   width: 100px;
   height: 200px;
 }
 #div {
   color: #00F578;
   border-color: #878787;
 }''');
 }
 
 void testPseudo() {
-  var errors = [];
+  var errors = <Message>[];
 
   final input = r'''
 html:lang(fr-ca) { quotes: '" ' ' "' }
 zoom: { }
 
 a:link { color: red }
 :link  { color: blue }
 
 a:focus { background: yellow }
 a:focus:hover { background: white }
@@ skipping 81 matching lines @@
 
 void testAttribute() {
   // TODO(terry): Implement
 }
 
 void testNegation() {
   // TODO(terry): Implement
 }
 
 void testHost() {
-  var errors = [];
+  var errors = <Message>[];
   var input = '@host { '
       ':scope {'
       'white-space: nowrap;'
       'overflow-style: marquee-line;'
       'overflow-x: marquee;'
       '}'
       '* { color: red; }'
       '*:hover { font-weight: bold; }'
       ':nth-child(odd) { color: blue; }'
       '}';
@@ skipping 14 matching lines @@
 *:hover {
   font-weight: bold;
 }
 :nth-child(odd) {
   color: #00f;
 }
 }''');
 }
 
 void testStringEscape() {
-  var errors = [];
+  var errors = <Message>[];
   var input = r'''a { foo: '{"text" : "a\\\""}' }''';
   var stylesheet = parseCss(input, errors: errors, opts: simpleOptions);
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
 
   expect(prettyPrint(stylesheet), r'''
 a {
   foo: '{"text" : "a\\\""}';
 }''');
 }
 
 // TODO(terry): Move to emitter_test.dart when real emitter exist.
 void testEmitter() {
-  var errors = [];
+  var errors = <Message>[];
   var input = '.foo { '
       'color: red; left: 20px; top: 20px; width: 100px; height:200px'
       '}'
       '#div {'
       'color : #00F578; border-color: #878787;'
       '}';
   var stylesheet = parseCss(input, errors: errors);
 
   expect(stylesheet != null, true);
   expect(errors.isEmpty, true, reason: errors.toString());
@@ skipping 25 matching lines @@
   test('Combinator', testCombinator);
   test('Wildcards', testWildcard);
   test('Pseudo', testPseudo);
   test('Attributes', testAttribute);
   test('Negation', testNegation);
   test('@host', testHost);
   test('stringEscape', testStringEscape);
   test('Parse List<int> as input', testArrayOfChars);
   test('Simple Emitter', testEmitter);
 }