Disallow legacy try-catch syntax.

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 85 matching lines @@
       '#{1} is a #{2}, not a constructor');
   static const FIELD_PARAMETER_NOT_ALLOWED = const MessageKind(
       'a field parameter is only allowed in generative constructors');
   static const INVALID_PARAMETER = const MessageKind(
       "cannot resolve parameter");
   static const NOT_INSTANCE_FIELD = const MessageKind(
       '#{1} 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 a variable in catch declaration');
+      'expected an identifier in catch declaration');
   static const EXTRA_CATCH_DECLARATION = const MessageKind(
-      'extra variable in catch declaration');
+      'extra parameter in catch declaration');
+  static const PARAMETER_WITH_TYPE_IN_CATCH = const MessageKind(
+      'cannot use type annotations in catch');
+  static const PARAMETER_WITH_MODIFIER_IN_CATCH = const MessageKind(
+      'cannot use modifiers in catch');
+  static const OPTIONAL_PARAMETER_IN_CATCH = const MessageKind(
+      'cannot use optional parameters in catch');
   static const UNBOUND_LABEL = const MessageKind(
       'cannot resolve label #{1}');
   static const NO_BREAK_TARGET = const MessageKind(
       'break statement not inside switch or loop');
   static const NO_CONTINUE_TARGET = const MessageKind(
       'continue statement not inside loop');
   static const EXISTING_LABEL = const MessageKind(
       'original declaration of duplicate label #{1}');
   static const DUPLICATE_LABEL = const MessageKind(
       'duplicate declaration of label #{1}');
@@ skipping 203 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);
 }