Issue 25686. Add 'var' for untyped unimplemented fields.

pkg/analysis_server/test/services/correction/fix_test.dart

Index: pkg/analysis_server/test/services/correction/fix_test.dart
diff --git a/pkg/analysis_server/test/services/correction/fix_test.dart b/pkg/analysis_server/test/services/correction/fix_test.dart
index ae6593ba3074545af79343594a5670bc65eaa26f..e01bf040e2563b5369bd7b1a0fd24a7d4b605bb0 100644
--- a/pkg/analysis_server/test/services/correction/fix_test.dart
+++ b/pkg/analysis_server/test/services/correction/fix_test.dart
@@ -2127,6 +2127,28 @@ main() {
 ''');
   }
 
+  test_createMissingOverrides_field_untyped() async {
+    resolveTestUnit('''
+class A {
+  var f;
+}
+
+class B implements A {
+}
+''');
+    await assertHasFix(
+        DartFixKind.CREATE_MISSING_OVERRIDES,
+        '''
+class A {
+  var f;
+}
+
+class B implements A {
+  var f;
+}
+''');
+  }
+
   test_createMissingOverrides_functionTypeAlias() async {
     resolveTestUnit('''
 typedef int Binary(int left, int right);