DAS: Fix ElementLocator for the SimpleIdentifier under a ConstructorSelector

With the `nodeCovering` utility, ElementLocator is given the
SimpleIdentifier _under_ a ConstructorSelector, in code like:

```dart
enum E {
  one, two.^new();
}
```

ElementLocator previously did not handle this SimpleIdentifier
correctly.

Change-Id: I32296dea2aaef6df33e56da23b77a4f83d06c9e6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/423063
Commit-Queue: Samuel Rawlins <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>
Reviewed-by: Konstantin Shcheglov <[email protected]>

Author: srawlins

pkg/analysis_server/lib/src/cider/rename.dart

@@ -12,7 +12,6 @@ import 'package:analysis_server/src/utilities/change_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element2.dart';
 import 'package:analyzer/source/line_info.dart';
-import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/micro/resolve_file.dart';
 import 'package:analyzer/src/dart/micro/utils.dart';
 import 'package:analyzer/src/generated/java_core.dart';
@@ -425,7 +424,7 @@ class CiderRenameComputer {
     var lineInfo = resolvedUnit.lineInfo;
     var offset = lineInfo.getOffsetOfLine(line) + column;
 
-    var node = NodeLocator(offset).searchWithin(resolvedUnit.unit);
+    var node = resolvedUnit.unit.nodeCovering(offset: offset);
     var element = getElementOfNode2(node);
 
     if (node == null || element == null) {

pkg/analysis_server/lib/src/services/refactoring/legacy/refactoring_manager.dart

@@ -20,6 +20,7 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element2.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/utilities/cancellation.dart';
+import 'package:analyzer/utilities/extensions/ast.dart';
 
 int test_resetCount = 0;
 
@@ -315,7 +316,7 @@ class RefactoringManager {
     } else if (kind == RefactoringKind.RENAME) {
       var resolvedUnit = await server.getResolvedUnit(file);
       if (resolvedUnit != null) {
-        var node = NodeLocator(offset).searchWithin(resolvedUnit.unit);
+        var node = resolvedUnit.unit.nodeCovering(offset: offset);
         var element = server.getElementOfNode(node, useMockForImport: true);
         if (node is RepresentationDeclaration) {
           var extensionType = node.parent;

pkg/analysis_server/test/edit/refactoring_test.dart

@@ -2210,8 +2210,8 @@ enum E {
 ''',
       feedbackValidator: (feedback) {
         var renameFeedback = feedback as RenameFeedback;
-        expect(renameFeedback.offset, 17);
-        expect(renameFeedback.length, 4);
+        expect(renameFeedback.offset, 18);
+        expect(renameFeedback.length, 3);
       },
     );
   }
@@ -2237,8 +2237,8 @@ enum E {
 ''',
       feedbackValidator: (feedback) {
         var renameFeedback = feedback as RenameFeedback;
-        expect(renameFeedback.offset, 24);
-        expect(renameFeedback.length, 5);
+        expect(renameFeedback.offset, 25);
+        expect(renameFeedback.length, 4);
       },
     );
   }

pkg/analyzer/lib/src/dart/ast/element_locator.dart

@@ -161,6 +161,14 @@ class _ElementMapper2 extends GeneralizingAstVisitor<Element2> {
       } else if (parent.name == node.endToken) {
         return parent.declaredFragment?.element;
       }
+    } else if (parent is ConstructorSelector) {
+      var parent2 = parent.parent;
+      if (parent2 is EnumConstantArguments) {
+        var parent3 = parent2.parent;
+        if (parent3 is EnumConstantDeclaration) {
+          return parent3.constructorElement2;
+        }
+      }
     } else if (parent is LibraryIdentifier) {
       var grandParent = parent.parent;
       if (grandParent is LibraryDirective) {