// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion The grammar for types does not allow multiple successive ?
/// operators on a type. That is, the grammar for types is nominally equivalent
/// to:
///  type' ::= functionType
///  | qualified typeArguments?
///  type ::= type' `?`?
///
/// @description Check that it is no error to have multiple ? but not in the type
/// declaration. Test type aliases
/// @author sgrekhov@unipro.ru

// Requirements=nnbd-strong
class A {}

typedef AAlias1 = A?;
typedef AAlias2 = AAlias1?;

main() {
  AAlias1 a1 = null;
  AAlias2 a2 = null;
}