Emit error on default values in typedefs.

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 400 matching lines @@
 
   static const DualKind NO_SUCH_LIBRARY_MEMBER = const DualKind(
       error: const MessageKind(
           'Error: "#{libraryName}" has no member named "#{memberName}".'),
       warning: const MessageKind(
           'Warning: "#{libraryName}" has no member named "#{memberName}".'));
 
   static const MessageKind CANNOT_INSTANTIATE_TYPEDEF = const MessageKind(
       'Error: Cannot instantiate typedef "#{typedefName}".');
 
+  static const MessageKind TYPEDEF_FORMAL_WITH_DEFAULT = const MessageKind(
+      "Error: A parameter of a typedef can't specify a default value.",
+      howToFix: "Remove the default value.",
+      examples: const ["""
+typedef void F([int arg = 0]);
+
+main() {
+  F f;
+}""", """
+typedef void F({int arg: 0});
+
+main() {
+  F f;
+}"""]);
+
   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 MessageKind CLASS_NAME_EXPECTED = const MessageKind(
       'Error: Class name expected.');
 
   static const MessageKind CANNOT_EXTEND = const MessageKind(
@@ skipping 639 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);
 }