diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart
index 0ff5f7956db..151400065a0 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart
@@ -47,10 +47,12 @@ class AddTypeAnnotation extends CorrectionProducer {
   @override
   Future<void> compute(ChangeBuilder builder) async {
     final node = this.node;
+
     if (node is SimpleFormalParameter) {
-      await _forSimpleFormalParameter(builder, node.name!, node);
+      await _forSimpleFormalParameter(builder, node);
       return;
     }
+
     if (node is DeclaredVariablePattern) {
       var type = node.matchedValueType;
       var keyword = node.keyword;
@@ -133,12 +135,17 @@ class AddTypeAnnotation extends CorrectionProducer {
         builder, declaredIdentifier.keyword, declaredIdentifier.name, type);
   }
 
-  Future<void> _forSimpleFormalParameter(ChangeBuilder builder, Token name,
-      SimpleFormalParameter parameter) async {
+  Future<void> _forSimpleFormalParameter(
+      ChangeBuilder builder, SimpleFormalParameter parameter) async {
     // Ensure that there isn't already a type annotation.
     if (parameter.type != null) {
       return;
     }
+    // Ensure that the parameter is named.
+    final name = parameter.name;
+    if (name == null) {
+      return;
+    }
     // Prepare the type.
     var type = parameter.declaredElement!.type;
     // TODO(scheglov) If the parameter is in a method declaration, and if the
diff --git a/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart
index a57a14fc0fa..df67d9b5dd3 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart
@@ -689,6 +689,14 @@ void f() {
 ''');
   }
 
+  Future<void> test_parameter_final_type_noName() async {
+    verifyNoTestUnitErrors = false;
+    await resolveTestCode('''
+typedef F = void Function(final int);
+''');
+    await assertNoAssistAt('final');
+  }
+
   @FailingTest(reason: '''
 This functionality is disabled in `AddTypeAnnotation._forSimpleFormalParameter`
 because `writeType` is writing the names of the parameters when it shouldn't.