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

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 0ced2882853f2a39c6eea0dd81d2ae7fe38e5ac0..a40c510ae53cca035c63f9b87ac998107a765ba5 100644
--- a/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
@@ -113,7 +113,7 @@ int a = 1 + 2;
     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 {
@@ -953,7 +953,7 @@ main(p) {
 ''');
   }
 
-  test_singleExpression_inExpressionBody() async {
+  test_singleExpression_inExpressionBody_ofClosure() async {
     indexTestUnit('''
 main() {
   print((x) => x.y * x.y + 1);
@@ -973,6 +973,46 @@ main() {
         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) {