Fix for 'Extract Local' in an expression function body.

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 'dart:convert';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
@@ skipping 95 matching lines @@
 
   test_checkInitialConditions_notPartOfFunction() async {
     indexTestUnit('''
 int a = 1 + 2;
 ''');
     _createRefactoringForString('1 + 2');
     // check conditions
     RefactoringStatus status = await refactoring.checkAllConditions();
     assertRefactoringStatus(status, RefactoringProblemSeverity.FATAL,
         expectedMessage:
-            'Expression inside of function must be selected to activate this refactoring.');
+            'Expression inside a function must be selected to activate this refactoring.');
   }
 
   test_checkInitialConditions_stringSelection_leadingQuote() async {
     indexTestUnit('''
 main() {
   var vvv = 'abc';
 }
 ''');
     _createRefactoringForString("'a");
     // apply refactoring
@@ skipping 819 matching lines @@
     // apply refactoring
     return _assertSuccessfulRefactoring('''
 main(p) {
   foo
   var res = p.bar;
   res.baz;
 }
 ''');
   }
 
-  test_singleExpression_inExpressionBody() async {
+  test_singleExpression_inExpressionBody_ofClosure() async {
     indexTestUnit('''
 main() {
   print((x) => x.y * x.y + 1);
 }
 ''');
     _createRefactoringForString('x.y');
     // apply refactoring
     await _assertSuccessfulRefactoring('''
 main() {
   print((x) {
     var res = x.y;
     return res * res + 1;
   });
 }
 ''');
     _assertSingleLinkedEditGroup(
         length: 3, offsets: [31, 53, 59], names: ['y']);
   }
 
+  test_singleExpression_inExpressionBody_ofFunction() async {
+    indexTestUnit('''
+foo(Point p) => p.x * p.x + p.y * p.y;
+class Point {int x; int y;}
+''');
+    _createRefactoringForString('p.x');
+    // apply refactoring
+    await _assertSuccessfulRefactoring('''
+foo(Point p) {
+  var res = p.x;
+  return res * res + p.y * p.y;
+}
+class Point {int x; int y;}
+''');
+    _assertSingleLinkedEditGroup(
+        length: 3, offsets: [21, 41, 47], names: ['x', 'i']);
+  }
+
+  test_singleExpression_inExpressionBody_ofMethod() async {
+    indexTestUnit('''
+class A {
+  foo(Point p) => p.x * p.x + p.y * p.y;
+}
+class Point {int x; int y;}
+''');
+    _createRefactoringForString('p.x');
+    // apply refactoring
+    await _assertSuccessfulRefactoring('''
+class A {
+  foo(Point p) {
+    var res = p.x;
+    return res * res + p.y * p.y;
+  }
+}
+class Point {int x; int y;}
+''');
+    _assertSingleLinkedEditGroup(
+        length: 3, offsets: [35, 57, 63], names: ['x', 'i']);
+  }
+
   test_singleExpression_inIfElseIf() {
     indexTestUnit('''
 main(int p) {
   if (p == 1) {
     print(1);
   } else if (p == 2) {
     print(2);
   }
 }
 ''');
@@ skipping 313 matching lines @@
   List<String> _getCoveringExpressions() {
     List<String> subExpressions = <String>[];
     for (int i = 0; i < refactoring.coveringExpressionOffsets.length; i++) {
       int offset = refactoring.coveringExpressionOffsets[i];
       int length = refactoring.coveringExpressionLengths[i];
       subExpressions.add(testCode.substring(offset, offset + length));
     }
     return subExpressions;
   }
 }