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

Index: pkg/analysis_server/test/services/refactoring/extract_local_test.dart
diff --git a/pkg/analysis_server/test/services/refactoring/extract_local_test.dart b/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
index baaeba55c4821eb1172e5d27633e60d9ba13bacc..6f657583c753b50bf5aa195d0a201653b9faa082 100644
--- a/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
@@ -9,9 +9,9 @@ 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';
 
 
@@ -718,6 +718,24 @@ main() {
 ''');
   }
 
+  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 {