RESOLVED_UNIT2 and RESOLVED_UNIT3 can be reused.

pkg/analyzer/lib/src/task/dart.dart

 // Copyright (c) 2015, 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 analyzer.src.task.dart;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 767 matching lines @@
 /**
  * The partially resolved [CompilationUnit] associated with a compilation unit.
  *
  * In addition to what is true of a [RESOLVED_UNIT1], tasks that use this value
  * as an input can assume that its directives have been resolved.
  *
  * The result is only available for [LibrarySpecificUnit]s.
  */
 final ResultDescriptor<CompilationUnit> RESOLVED_UNIT2 =
     new ResultDescriptor<CompilationUnit>('RESOLVED_UNIT2', null,
-        cachingPolicy: AST_CACHING_POLICY);
+        cachingPolicy: AST_REUSABLE_CACHING_POLICY);
 
 /**
  * The partially resolved [CompilationUnit] associated with a compilation unit.
  *
  * Tasks that use this value as an input can assume that the [SimpleIdentifier]s
  * at all declaration sites have been bound to the element defined by the
  * declaration, including the constants defined in an 'enum' declaration.
  *
  * The result is only available for [LibrarySpecificUnit]s.
  */
 final ResultDescriptor<CompilationUnit> RESOLVED_UNIT3 =
     new ResultDescriptor<CompilationUnit>('RESOLVED_UNIT3', null,
-        cachingPolicy: AST_CACHING_POLICY);
+        cachingPolicy: AST_REUSABLE_CACHING_POLICY);
 
 /**
  * The partially resolved [CompilationUnit] associated with a compilation unit.
  *
  * In addition to what is true of a [RESOLVED_UNIT3], tasks that use this value
  * as an input can assume that the types associated with type bounds have been
  * resolved.
  *
  * The result is only available for [LibrarySpecificUnit]s.
  */
@@ skipping 5541 matching lines @@
 
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.removeLast();
     return true;
   }
 }