LanguageFeatures/nnbd/static_errors_A32_t07.dart

// 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 It is a warning to use a null aware operator (?., ?.., ??, ??=,
 * or ...?) on an expression of type T if T is strictly non-nullable.
 *
 * @description Check it is a warning to use a null aware operator (?., ?.., ??,
 * ??=, or ...?) on a strictly non-nullable receiver. Test <T extends Object>
 * @author sgrekhov@unipro.ru
 * @issue 39598
 * @issue 39714
 */

test<T extends Object>(T t) {
  t?.toString();
//^
// [cfe] Operand of null-aware operation '?.' has type 'T' which excludes null.
// ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  t?..toString();
//^
// [cfe] Operand of null-aware operation '?..' has type 'T' which excludes null.
// ^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  t ?? t;
//^
// [cfe] Operand of null-aware operation '??' has type 'T' which excludes null.
//     ^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
  t ??= t;
//^
// [cfe] Operand of null-aware operation '??=' has type 'T' which excludes null.
//      ^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
  List<T> clist = [t, t];
  List<T> alist = [t, t, ...? clist];
  //                     ^^^^
  // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  //                          ^
  // [cfe] Operand of null-aware operation '...?' has type 'List<T>' which excludes null.
}

main() {
  test<String>("Lily was here");
}