Issue 25313. Skip constructor names and named expressions.

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 212 matching lines @@
       int numTrailing = countTrailingWhitespaces(selectionStr);
       int offset = selectionRange.offset + numLeading;
       int end = selectionRange.end - numTrailing;
       selectionRange = new SourceRange(offset, end - offset);
     }
     // get covering node
     AstNode coveringNode =
         new NodeLocator(selectionRange.offset, selectionRange.end)
             .searchWithin(unit);
     // compute covering expressions
-    for (AstNode node = coveringNode;
-        node is Expression || node is ArgumentList;
-        node = node.parent) {
+    for (AstNode node = coveringNode;; node = node.parent) {

[Brian Wilkerson, 2015/12/27 16:49:42]

Perhaps replace the condition with "node != null"? It feels safer, but perhaps
it's not necessary.

       AstNode parent = node.parent;
+      // skip some nodes
+      if (node is ArgumentList ||
+          node is AssignmentExpression ||
+          node is NamedExpression ||
+          node is TypeArgumentList) {
+        continue;
+      }
+      if (node is ConstructorName || node is Label || node is TypeName) {
+        rootExpression = null;
+        coveringExpressionOffsets.clear();
+        coveringExpressionLengths.clear();
+        continue;
+      }
+      // cannot extract the name part of a property access
+      if (parent is PrefixedIdentifier && parent.identifier == node ||
+          parent is PropertyAccess && parent.propertyName == node) {
+        continue;
+      }
+      // stop if not an Expression
+      if (node is! Expression) {
+        break;
+      }
       // stop at void method invocations
       if (node is MethodInvocation) {
         MethodInvocation invocation = node;
         Element element = invocation.methodName.bestElement;
         if (element is ExecutableElement &&
             element.returnType != null &&
             element.returnType.isVoid) {
           if (rootExpression == null) {
             return new RefactoringStatus.fatal(
                 'Cannot extract the void expression.',
                 newLocation_fromNode(node));
           }
           break;
         }
       }
-      // skip ArgumentList
-      if (node is ArgumentList) {
-        continue;
-      }
-      // skip AssignmentExpression
-      if (node is AssignmentExpression) {
-        continue;
-      }
-      // cannot extract the name part of a property access
-      if (parent is PrefixedIdentifier && parent.identifier == node ||
-          parent is PropertyAccess && parent.propertyName == node) {
-        continue;
-      }
       // fatal selection problems
       if (coveringExpressionOffsets.isEmpty) {
         if (node is SimpleIdentifier) {
           if (node.inDeclarationContext()) {
             return new RefactoringStatus.fatal(
                 'Cannot extract the name part of a declaration.',
                 newLocation_fromNode(node));
           }
           Element element = node.bestElement;
           if (element is FunctionElement || element is MethodElement) {
@@ skipping 403 matching lines @@
 
   _TokenLocalElementVisitor(this.map);
 
   visitSimpleIdentifier(SimpleIdentifier node) {
     Element element = node.staticElement;
     if (element is LocalVariableElement) {
       map[node.token] = element;
     }
   }
 }