Issue 22833. Quick Assist to convert for-each into for-index.

pkg/analysis_server/lib/src/services/refactoring/extract_local.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.src.refactoring.extract_local;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
@@ skipping 33 matching lines @@
   final List<String> names = <String>[];
   final List<int> offsets = <int>[];
   final List<int> lengths = <int>[];
 
   Expression rootExpression;
   Expression singleExpression;
   bool wholeStatementExpression = false;
   String stringLiteralPart;
   final List<SourceRange> occurrences = <SourceRange>[];
   final Map<Element, int> elementIds = <Element, int>{};
-  final Set<String> excludedVariableNames = new Set<String>();
+  Set<String> excludedVariableNames = new Set<String>();
 
   ExtractLocalRefactoringImpl(
       this.unit, this.selectionOffset, this.selectionLength) {
     unitElement = unit.element;
     selectionRange = new SourceRange(selectionOffset, selectionLength);
     utils = new CorrectionUtils(unit);
   }
 
   @override
   String get refactoringName => 'Extract Local Variable';
@@ skipping 22 matching lines @@
     RefactoringStatus result = new RefactoringStatus();
     // selection
     result.addStatus(_checkSelection());
     if (result.hasFatalError) {
       return new Future.value(result);
     }
     // occurrences
     _prepareOccurrences();
     _prepareOffsetsLengths();
     // names
-    _prepareExcludedNames();
+    excludedVariableNames =
+        utils.findPossibleLocalVariableConflicts(selectionOffset);
     _prepareNames();
     // done
     return new Future.value(result);
   }
 
   @override
   RefactoringStatus checkName() {
     return validateVariableName(name);
   }
 
@@ skipping 256 matching lines @@
         node is BinaryExpression ||
         node is ParenthesizedExpression ||
         node is PrefixExpression ||
         node is Literal ||
         node is MapLiteralEntry) {
       return _isPartOfConstantExpression(node.parent);
     }
     return false;
   }
 
-  void _prepareExcludedNames() {
-    excludedVariableNames.clear();
-    AstNode enclosingNode =
-        new NodeLocator.con1(selectionOffset).searchWithin(unit);
-    Block enclosingBlock = enclosingNode.getAncestor((node) => node is Block);
-    if (enclosingBlock != null) {
-      SourceRange newVariableVisibleRange =
-          rangeStartEnd(selectionRange, enclosingBlock.end);
-      ExecutableElement enclosingExecutable =
-          getEnclosingExecutableElement(enclosingNode);
-      if (enclosingExecutable != null) {
-        visitChildren(enclosingExecutable, (Element element) {
-          if (element is LocalElement) {
-            SourceRange elementRange = element.visibleRange;
-            if (elementRange != null &&
-                elementRange.intersects(newVariableVisibleRange)) {
-              excludedVariableNames.add(element.displayName);
-            }
-          }
-          return true;
-        });
-      }
-    }
-  }
-
   void _prepareNames() {
     names.clear();
     if (stringLiteralPart != null) {
       names.addAll(getVariableNameSuggestionsForText(
           stringLiteralPart, excludedVariableNames));
     } else if (singleExpression != null) {
       names.addAll(getVariableNameSuggestionsForExpression(
           singleExpression.staticType, singleExpression,
           excludedVariableNames));
     }
@@ skipping 213 matching lines @@
 
   _TokenLocalElementVisitor(this.map);
 
   visitSimpleIdentifier(SimpleIdentifier node) {
     Element element = node.staticElement;
     if (element is LocalVariableElement) {
       map[node.token] = element;
     }
   }
 }