Correctly handle const constructors with type parameters.

lib/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.
 
 class MessageKind {
   final String template;
   const MessageKind(this.template);
 
   static const GENERIC = const MessageKind('#{1}');
 
@@ skipping 135 matching lines @@
   static const SWITCH_INVALID = const MessageKind(
       "switch cases contain invalid expressions.");
 
   static const INVALID_ARGUMENT_AFTER_NAMED = const MessageKind(
       'non-named argument after named argument');
 
   static const NOT_A_COMPILE_TIME_CONSTANT = const MessageKind(
       'not a compile-time constant');
   static const CYCLIC_COMPILE_TIME_CONSTANTS = const MessageKind(
       'cycle in the compile-time constant computation');
+  static const CONSTRUCTOR_IS_NOT_CONST = const MessageKind(
+      'constructor is not a const constructor');
 
   static const KEY_NOT_A_STRING_LITERAL = const MessageKind(
       'map-literal key not a string literal');
 
   static const NO_SUCH_LIBRARY_MEMBER = const MessageKind(
       '#{1} has no member named #{2}');
 
   static const CANNOT_INSTANTIATE_INTERFACE = const MessageKind(
       "cannot instantiate interface '#{1}'");
 
@@ skipping 176 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, List arguments)
     : super(kind, arguments);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, List arguments)
     : super(kind, arguments);
 }