Add parser support for covariant parameters

pkg/analyzer/lib/src/dart/error/syntactic_errors.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.
 
 /**
  * The errors produced during syntactic analysis (scanning and parsing).
  */
 library analyzer.src.dart.error.syntactic_errors;
 
 import 'package:analyzer/error/error.dart';
@@ skipping 64 matching lines @@
   static const ParserErrorCode CLASS_IN_CLASS = const ParserErrorCode(
       'CLASS_IN_CLASS',
       "Classes can't be declared inside other classes.",
       "Try moving the class to the top-level.");
 
   static const ParserErrorCode COLON_IN_PLACE_OF_IN = const ParserErrorCode(
       'COLON_IN_PLACE_OF_IN',
       "For-in loops use 'in' rather than a colon.",
       "Try replacing the colon with the keyword 'in'.");
 
+  static const ParserErrorCode CONST_AND_COVARIANT = const ParserErrorCode(
+      'CONST_AND_COVARIANT',
+      "Members can't be declared to be both 'const' and 'covariant'.",
+      "Try removing either the 'const' or 'covariant' keyword.");
+
   static const ParserErrorCode CONST_AND_FINAL = const ParserErrorCode(
       'CONST_AND_FINAL',
       "Members can't be declared to be both 'const' and 'final'.",
       "Try removing either the 'const' or 'final' keyword.");
 
   static const ParserErrorCode CONST_AND_VAR = const ParserErrorCode(
       'CONST_AND_VAR',
       "Members can't be declared to be both 'const' and 'var'.",
       "Try removing either the 'const' or 'var' keyword.");
 
@@ skipping 40 matching lines @@
   static const ParserErrorCode CONTINUE_OUTSIDE_OF_LOOP = const ParserErrorCode(
       'CONTINUE_OUTSIDE_OF_LOOP',
       "A continue statement can't be used outside of a loop or switch statement.",
       "Try removing the continue statement.");
 
   static const ParserErrorCode CONTINUE_WITHOUT_LABEL_IN_CASE = const ParserErrorCode(
       'CONTINUE_WITHOUT_LABEL_IN_CASE',
       "A continue statement in a switch statement must have a label as a target.",
       "Try adding a label associated with one of the case clauses to the continue statement.");
 
+  static const ParserErrorCode COVARIANT_AFTER_VAR = const ParserErrorCode(
+      'COVARIANT_AFTER_VAR',
+      "The modifier 'covariant' should be before the modifier 'var'.",
+      "Try re-ordering the modifiers.");
+
+  static const ParserErrorCode COVARIANT_AND_STATIC = const ParserErrorCode(
+      'COVARIANT_AND_STATIC',
+      "Members can't be declared to be both 'covariant' and 'static'.",
+      "Try removing either the 'covariant' or 'static' keyword.");
+
+  static const ParserErrorCode COVARIANT_TOP_LEVEL_DECLARATION =
+      const ParserErrorCode(
+          'COVARIANT_TOP_LEVEL_DECLARATION',
+          "Top-level declarations can't be declared to be covariant.",
+          "Try removing the keyword 'covariant'.");
+
+  static const ParserErrorCode COVARIANT_CONSTRUCTOR = const ParserErrorCode(
+      'COVARIANT_CONSTRUCTOR',
+      "A constructor can't be declared to be 'covariant'.",
+      "Try removing the keyword 'covariant'.");
+
   static const ParserErrorCode DEFAULT_VALUE_IN_FUNCTION_TYPE =
       const ParserErrorCode(
           'DEFAULT_VALUE_IN_FUNCTION_TYPE',
           "Parameters in a function type cannot have default values",
           "Try removing the default value.");
 
   static const ParserErrorCode DIRECTIVE_AFTER_DECLARATION =
       const ParserErrorCode(
           'DIRECTIVE_AFTER_DECLARATION',
           "Directives must appear before any declarations.",
@@ skipping 160 matching lines @@
       'FACTORY_WITHOUT_BODY',
       "A non-redirecting 'factory' constructor must have a body.",
       "Try adding a body to the constructor.");
 
   static const ParserErrorCode FIELD_INITIALIZER_OUTSIDE_CONSTRUCTOR =
       const ParserErrorCode(
           'FIELD_INITIALIZER_OUTSIDE_CONSTRUCTOR',
           "Field formal parameters can only be used in a constructor.",
           "Try replacing the field formal parameter with a normal parameter.");
 
+  static const ParserErrorCode FINAL_AND_COVARIANT = const ParserErrorCode(
+      'FINAL_AND_COVARIANT',
+      "Members can't be declared to be both 'final' and 'covariant'.",
+      "Try removing either the 'final' or 'covariant' keyword.");
+
   static const ParserErrorCode FINAL_AND_VAR = const ParserErrorCode(
       'FINAL_AND_VAR',
       "Members can't be declared to be both 'final' and 'var'.",
       "Try removing the keyword 'var'.");
 
   static const ParserErrorCode FINAL_CLASS = const ParserErrorCode(
       'FINAL_CLASS',
       "Classes can't be declared to be 'final'.",
       "Try removing the keyword 'final'.");
 
@@ skipping 615 matching lines @@
    */
   const ParserErrorCode(String name, String message, [String correction])
       : super(name, message, correction);
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.ERROR;
 
   @override
   ErrorType get type => ErrorType.SYNTACTIC_ERROR;
 }