Emit compile-time error on 'const' formal parameters.

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;
 
 const DONT_KNOW_HOW_TO_FIX = "";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 532 matching lines @@
 
 main() {
   F f;
 }""", """
 typedef void F({int arg: 0});
 
 main() {
   F f;
 }"""]);
 
+  static const MessageKind FORMAL_DECLARED_CONST = const MessageKind(
+      "Error: A formal parameter can't be declared const.",
+      howToFix: "Try removing 'const'.",
+      examples: const ["""
+foo(const x) {}
+main() => foo(42);
+""", """
+foo({const x}) {}
+main() => foo(42);
+""", """
+foo([const x]) {}
+main() => foo(42);
+"""]);
+
   static const MessageKind CANNOT_INSTANTIATE_TYPE_VARIABLE = const MessageKind(
       'Error: Cannot instantiate type variable "#{typeVariableName}".');
 
   static const MessageKind CYCLIC_TYPE_VARIABLE = const MessageKind(
       'Warning: Type variable "#{typeVariableName}" is a supertype of itself.');
 
   static const CYCLIC_TYPEDEF = const MessageKind(
       "Error: A typedef can't refer to itself.",
       howToFix: "Try removing all references to '#{typedefName}' "
                 "in the definition of '#{typedefName}'.",
@@ skipping 701 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }