Issue 18895. Convert an expression function body into the block function body when Extract Local.

pkg/analysis_server/test/services/refactoring/extract_local_test.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 test.services.refactoring.extract_local;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/refactoring/extract_local.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
-import '../../reflective_tests.dart';
 import 'package:unittest/unittest.dart';
 
+import '../../reflective_tests.dart';
 import 'abstract_refactoring.dart';
 
 
 main() {
   groupSep = ' | ';
   runReflectiveTests(ExtractLocalTest);
 }
 
 
 @ReflectiveTestCase()
@@ skipping 686 matching lines @@
   int get foo => 42;
 }
 main() {
   A a = new A();
   var res = a.foo;
   int b = 1 + res; // marker
 }
 ''');
   }
 
+  test_singleExpression_inExpressionBody() {
+    indexTestUnit('''
+main() {
+  print((x) => x.y * x.y + 1);
+}
+''');
+    _createRefactoringForString('x.y');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+main() {
+  print((x) {
+    var res = x.y;
+    return res * res + 1;
+  });
+}
+''');
+  }
+
   test_singleExpression_inMethod() {
     indexTestUnit('''
 class A {
   main() {
     print(1 + 2);
   }
 }
 ''');
     _createRefactoringForString('1 + 2');
     // apply refactoring
@@ skipping 166 matching lines @@
     int length = search.length;
     _createRefactoring(offset, length);
   }
 
   void _createRefactoringWithSuffix(String selectionSearch, String suffix) {
     int offset = findOffset(selectionSearch + suffix);
     int length = selectionSearch.length;
     _createRefactoring(offset, length);
   }
 }