Finish refactoring FixProcessor to use ChangeBuilder

pkg/analyzer_plugin/lib/src/utilities/change_builder/change_builder_dart.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.
 
 import 'dart:async';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
+import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     hide Element, ElementKind;
 import 'package:analyzer_plugin/src/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/src/utilities/string_utilities.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
 import 'package:analyzer_plugin/utilities/range_factory.dart';
@@ skipping 342 matching lines @@
       write(prefix);
       writeln('}');
     }
   }
 
   @override
   void writeParameterMatchingArgument(
       Expression argument, int index, Set<String> usedNames) {
     // append type name
     DartType type = argument.bestType;
+    if (type == null || type.isBottom || type.isDartCoreNull) {
+      type = DynamicTypeImpl.instance;
+    }
     if (writeType(type, addSupertypeProposals: true, groupName: 'TYPE$index')) {
       write(' ');
     }
     // append parameter name
     if (argument is NamedExpression) {
       write(argument.name.label.name);
     } else {
       List<String> suggestions =
           _getParameterNameSuggestions(usedNames, type, argument, index);
       String favorite = suggestions[0];
@@ skipping 201 matching lines @@
         result.add(name);
         break;
       }
       // next character
       c = c + 1;
     }
   }
 
   void _addSuperTypeProposals(
       LinkedEditBuilder builder, DartType type, Set<DartType> alreadyAdded) {
-    if (type != null &&
-        type.element is ClassElement &&
-        alreadyAdded.add(type)) {
-      ClassElement element = type.element as ClassElement;
-      builder.addSuggestion(LinkedEditSuggestionKind.TYPE, element.name);
-      _addSuperTypeProposals(builder, element.supertype, alreadyAdded);
-      for (InterfaceType interfaceType in element.interfaces) {
+    if (type is InterfaceType && alreadyAdded.add(type)) {
+      builder.addSuggestion(LinkedEditSuggestionKind.TYPE, type.displayName);
+      _addSuperTypeProposals(builder, type.superclass, alreadyAdded);
+      for (InterfaceType interfaceType in type.interfaces) {
         _addSuperTypeProposals(builder, interfaceType, alreadyAdded);
       }
     }
   }
 
   String _getBaseNameFromExpression(Expression expression) {
     String name = null;
     // e as Type
     if (expression is AsExpression) {
       AsExpression asExpression = expression as AsExpression;
@@ skipping 176 matching lines @@
         methodBeingCopied: methodBeingCopied);
     if (typeSource.isNotEmpty) {
       return '$typeSource $name';
     }
     return name;
   }
 
   /**
    * Returns the source to reference [type] in this [CompilationUnit].
    *
-   * Fills [librariesToImport] with [LibraryElement]s whose elements are
-   * used by the generated source, but not imported.
+   * Causes any libraries whose elements are used by the generated source, to be
+   * imported.
    */
   String _getTypeSource(DartType type, ClassElement enclosingClass,
       ExecutableElement enclosingExecutable,
       {ExecutableElement methodBeingCopied, StringBuffer parametersBuffer}) {
     StringBuffer buffer = new StringBuffer();
     // type parameter
     if (!_isTypeVisible(type, enclosingClass, enclosingExecutable,
         methodBeingCopied: methodBeingCopied)) {
       return 'dynamic';
     }
@@ skipping 530 matching lines @@
   }
 }
 
 class _InsertionDescription {
   final int offset;
   final bool insertEmptyLineBefore;
   final bool insertEmptyLineAfter;
   _InsertionDescription(
       this.offset, this.insertEmptyLineBefore, this.insertEmptyLineAfter);
 }