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

pkg/analysis_server/lib/src/services/refactoring/extract_local.dart

Index: pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
diff --git a/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart b/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
index e01942c8e05de8777498f49b48d66eb2a912d35c..81676c1e6ab0ead1c62cb912f3bce55e2c983748 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
@@ -51,7 +51,7 @@ class ExtractLocalRefactoringImpl extends RefactoringImpl
   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) {
@@ -94,7 +94,8 @@ class ExtractLocalRefactoringImpl extends RefactoringImpl
     _prepareOccurrences();
     _prepareOffsetsLengths();
     // names
-    _prepareExcludedNames();
+    excludedVariableNames =
+        utils.findPossibleLocalVariableConflicts(selectionOffset);
     _prepareNames();
     // done
     return new Future.value(result);
@@ -371,31 +372,6 @@ class ExtractLocalRefactoringImpl extends RefactoringImpl
     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) {