[Completion] Show enum constants when completion is in the declaration.

Fixes #56971

Change-Id: Ib33a58e774f5540c426f5d5ffb7a387414dcf9f9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/408600
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Keerti Parthasarathy <[email protected]>

Author: keertip

pkg/analysis_server/lib/src/services/completion/dart/candidate_suggestion.dart

@@ -328,17 +328,25 @@ final class FieldSuggestion extends CandidateSuggestion with MemberSuggestion {
   @override
   final InterfaceElement2? referencingInterface;
 
+  /// Indicates the context, whether the completion is in the body of the
+  /// declaration.
+  final bool isInDeclaration;
+
   /// Initialize a newly created candidate suggestion to suggest the [element].
   FieldSuggestion({
     required this.element,
     required super.matcherScore,
     required this.referencingInterface,
+    required this.isInDeclaration,
   });
 
   @override
   String get completion {
     if (element.isEnumConstant) {
       var constantName = element.name3;
+      if (isInDeclaration) {
+        return '$constantName';
+      }
       var enumName = element.enclosingElement2.displayName;
       return '$enumName.$constantName';
     }

pkg/analysis_server/lib/src/services/completion/dart/declaration_helper.dart

@@ -1247,6 +1247,7 @@ class DeclarationHelper {
         _suggestProperty(
           accessor: accessor,
           referencingInterface: referencingInterface,
+          isInDeclaration: true,
         );
       }
     }
@@ -1256,13 +1257,18 @@ class DeclarationHelper {
         _suggestProperty(
           accessor: accessor,
           referencingInterface: referencingInterface,
+          isInDeclaration: true,
         );
       }
     }
 
     for (var field in element.fields2) {
       if (!field.isSynthetic && (!mustBeStatic || field.isStatic)) {
-        _suggestField(field: field, referencingInterface: referencingInterface);
+        _suggestField(
+          field: field,
+          referencingInterface: referencingInterface,
+          isInDeclaration: true,
+        );
       }
     }
 
@@ -1777,6 +1783,7 @@ class DeclarationHelper {
   void _suggestField({
     required FieldElement2 field,
     InterfaceElement2? referencingInterface,
+    bool isInDeclaration = false,
   }) {
     if (visibilityTracker.isVisible(element: field, importData: null)) {
       if ((mustBeAssignable && field.setter2 == null) ||
@@ -1789,6 +1796,7 @@ class DeclarationHelper {
           element: field,
           matcherScore: matcherScore,
           referencingInterface: referencingInterface,
+          isInDeclaration: isInDeclaration,
         );
         collector.addSuggestion(suggestion);
       }
@@ -1933,6 +1941,7 @@ class DeclarationHelper {
     bool ignoreVisibility = false,
     ImportData? importData,
     InterfaceElement2? referencingInterface,
+    bool isInDeclaration = false,
   }) {
     if (ignoreVisibility ||
         visibilityTracker.isVisible(
@@ -1959,6 +1968,7 @@ class DeclarationHelper {
                 element: variable,
                 matcherScore: matcherScore,
                 referencingInterface: referencingInterface,
+                isInDeclaration: isInDeclaration,
               );
               collector.addSuggestion(suggestion);
             }
@@ -2043,6 +2053,7 @@ class DeclarationHelper {
                     element: variable,
                     matcherScore: matcherScore,
                     referencingInterface: null,
+                    isInDeclaration: false,
                   );
                   collector.addSuggestion(suggestion);
                 }

pkg/analysis_server/test/services/completion/dart/declaration/enum_test.dart

@@ -15,7 +15,6 @@ void main() {
 
 @reflectiveTest
 class EnumTest extends AbstractCompletionDriverTest with EnumTestCases {
-  @failingTest
   Future<void> test_inside_implicitThis_constants() async {
     await computeSuggestions('''
 enum E {

pkg/analysis_server/test/services/completion/dart/location/enum_declaration_test.dart

@@ -375,6 +375,27 @@ suggestions
   Test {}
     kind: identifier
     selection: 6
+''');
+  }
+
+  Future<void> test_values() async {
+    allowedIdentifiers = {'first', 'last'};
+    includeKeywords = false;
+    await computeSuggestions('''
+enum E {
+  first,
+  last;
+
+  List<E> get all => [^];
+}
+''');
+
+    assertResponse(r'''
+suggestions
+  first
+    kind: enumConstant
+  last
+    kind: enumConstant
 ''');
   }
 }