Report error when using initializing formals in redirecting constructors.

sdk/lib/_internal/compiler/implementation/warnings.dart

 // Copyright (c) 2011, 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.
 
 part of dart2js;
 
 class MessageKind {
   final String template;
   const MessageKind(this.template);
 
@@ skipping 102 matching lines @@
   static const SUPER_INITIALIZER_IN_OBJECT = const MessageKind(
       "'Object' cannot have a super initializer");
   static const DUPLICATE_SUPER_INITIALIZER = const MessageKind(
       'cannot have more than one super initializer');
   static const INVALID_ARGUMENTS = const MessageKind(
       "arguments do not match the expected parameters of #{methodName}");
   static const NO_MATCHING_CONSTRUCTOR = const MessageKind(
       "super call arguments and constructor parameters don't match");
   static const NO_MATCHING_CONSTRUCTOR_FOR_IMPLICIT = const MessageKind(
       "implicit super call arguments and constructor parameters don't match");
-  static const FIELD_PARAMETER_NOT_ALLOWED = const MessageKind(
-      'a field parameter is only allowed in generative constructors');
+  static const INITIALIZING_FORMAL_NOT_ALLOWED = const MessageKind(
+      'an initializing formal parameter is only allowed in '
+      'non-redirecting generative constructors');
   static const INVALID_PARAMETER = const MessageKind(
       "cannot resolve parameter");
   static const NOT_INSTANCE_FIELD = const MessageKind(
       '#{fieldName} is not an instance field');
   static const NO_CATCH_NOR_FINALLY = const MessageKind(
       "expected 'catch' or 'finally'");
   static const EMPTY_CATCH_DECLARATION = const MessageKind(
       'expected an identifier in catch declaration');
   static const EXTRA_CATCH_DECLARATION = const MessageKind(
       'extra parameter in catch declaration');
@@ skipping 500 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, [Map arguments = const {}])
     : super(kind, arguments);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, [Map arguments = const {}])
     : super(kind, arguments);
 }