Use HasToJson when set Reponse/Notification parameters.

pkg/analysis_server/lib/src/computer/computer_overrides.dart

 // Copyright (c) 2014, 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.
 
 library computer.overrides;
 
+import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/computer/element.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart' as engine;
 
 
 /**
  * A computer for class member overrides in a Dart [CompilationUnit].
  */
 class DartUnitOverridesComputer {
   final CompilationUnit _unit;
 
   final List<Override> _overrides = <Override>[];
   engine.ClassElement _currentClass;
 
   DartUnitOverridesComputer(this._unit);
 
   /**
    * Returns the computed occurrences, not `null`.
    */
-  List<Map<String, Object>> compute() {
+  List<Override> compute() {
     for (CompilationUnitMember unitMember in _unit.declarations) {
       if (unitMember is ClassDeclaration) {
         _currentClass = unitMember.element;
         for (ClassMember classMember in unitMember.members) {
           if (classMember is MethodDeclaration) {
             SimpleIdentifier nameNode = classMember.name;
             _addOverride(nameNode.offset, nameNode.length, nameNode.name);
           }
           if (classMember is FieldDeclaration) {
             List<VariableDeclaration> fields = classMember.fields.variables;
@@ skipping 59 matching lines @@
     member = classElement.lookUpSetter(name + '=', library);
     if (member != null) {
       return member;
     }
     // not found
     return null;
   }
 }
 
 
-class Override {
+class Override implements HasToJson {
   final int offset;
   final int length;
   final Element superclassElement;
   final List<Element> interfaceElements;
 
   Override(this.offset, this.length, this.superclassElement,
       this.interfaceElements);
 
   factory Override.fromJson(Map<String, Object> map) {
     int offset = map[OFFSET];
@@ skipping 32 matching lines @@
       json[INTERFACE_ELEMENTS] = interfaceElements.map((element) {
         return element.toJson();
       }).toList();
     }
     return json;
   }
 
   @override
   String toString() => toJson().toString();
 }