Specify types in generated closure args.

pkg/analysis_server/lib/src/services/completion/dart/utilities.dart

 // Copyright (c) 2017, 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.
 
 /**
  * A collection of utility methods used by completion contributors.
  */
 import 'package:analysis_server/protocol/protocol_generated.dart' as protocol
     show Element, ElementKind;
 import 'package:analysis_server/src/ide_options.dart';
@@ skipping 171 matching lines @@
     DartType type = param.type;
     if (type is InterfaceType && isDartList(type)) {
       List<DartType> typeArguments = type.typeArguments;
       if (typeArguments.length == 1) {
         DartType typeArg = typeArguments.first;
         String typeInfo = !typeArg.isDynamic ? '<${typeArg.name}>' : '';
         return '$typeInfo[]';
       }
     }
     if (type is FunctionType) {
-      String params = type.parameters.map((p) => p.name).join(', ');
+      String params = type.parameters
+          .map((p) => '${getTypeString(p.type)}${p.name}')
+          .join(', ');
       //TODO(pq): consider adding a `TODO:` message in generated stub
       return '($params) {}';
     }
     //TODO(pq): support map literals
   }
   return null;
 }
 
+String getTypeString(DartType type) => type.isDynamic ? '' : '${type.name} ';
+
 bool isDartList(DartType type) {
   ClassElement element = type.element;
   if (element != null) {
     return element.name == "List" && element.library.isDartCore;
   }
   return false;
 }
 
 /**
  * Return `true` if the @deprecated annotation is present on the given [node].
@@ skipping 33 matching lines @@
     if (typeArgs != null) {
       //TODO (danrubel) include type arguments
     }
     return name;
   } else if (type is GenericFunctionType) {
     // TODO(brianwilkerson) Implement this.
   }
   return DYNAMIC;
 }
 
+//TODO(pq): fix to use getDefaultStringParameterValue()
 String _getDefaultValue(ParameterElement param) => 'null';