Fix for 'Rename Local' refactoring without tasks.

pkg/analysis_server/lib/src/services/refactoring/refactoring.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 services.refactoring;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart'
     show RefactoringMethodParameter, SourceChange;
@@ skipping 379 matching lines @@
     if (element is ImportElement) {
       return new RenameImportRefactoringImpl(searchEngine, element);
     }
     if (element is LabelElement) {
       return new RenameLabelRefactoringImpl(searchEngine, element);
     }
     if (element is LibraryElement) {
       return new RenameLibraryRefactoringImpl(searchEngine, element);
     }
     if (element is LocalElement) {
-      return new RenameLocalRefactoringImpl(searchEngine, element);
+      return new RenameLocalRefactoringImpl(searchEngine, astProvider, element);
     }
     if (element.enclosingElement is ClassElement) {
       return new RenameClassMemberRefactoringImpl(searchEngine, element);
     }
     return null;
   }
 
   /**
    * Returns the human-readable description of the kind of element being renamed
    * (such as “class” or “function type alias”).
@@ skipping 14 matching lines @@
    * Validates that the [newName] is a valid identifier and is appropriate for
    * the type of the [Element] being renamed.
    *
    * It does not perform all the checks (such as checking for conflicts with any
    * existing names in any of the scopes containing the current name), as many
    * of these checkes require search engine. Use [checkFinalConditions] for this
    * level of checking.
    */
   RefactoringStatus checkNewName();
 }
+
+/**
+ * Cache for accessing resolved [CompilationUnit]s by [Element]s.
+ *
+ * Must by short-lived.
+ *
+ * TODO(scheglov) consider moving to request-bound object.
+ */
+class ResolvedUnitCache {
+  final AstProvider _astProvider;
+  final Map<CompilationUnitElement, CompilationUnit> _map = {};
+
+  ResolvedUnitCache(this._astProvider, [CompilationUnit unit]) {
+    if (unit != null) {
+      _map[unit.element] = unit;
+    }
+  }
+
+  Future<CompilationUnit> getUnit(Element element) async {
+    CompilationUnitElement unitElement =
+        element.getAncestor((e) => e is CompilationUnitElement)
+            as CompilationUnitElement;
+    CompilationUnit unit = _map[unitElement];
+    if (unit == null) {
+      unit = await _astProvider.getResolvedUnitForElement(element);
+      _map[unitElement] = unit;
+    }
+    return unit;
+  }
+}