LanguageFeatures/nnbd/static_errors_A32_t01.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.
/// @author sgrekhov@unipro.ru
/// @issue 39598


class A {
  test() {}
}

class C extends A {}

main() {
  A a = A();
  C c = C();
  a?.test();
//^
// [cfe] Operand of null-aware operation '?.' has type 'A' which excludes null.
// ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  a?..test();
//^
// [cfe] Operand of null-aware operation '?..' has type 'A' which excludes null.
// ^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  a ?? c;
//^
// [cfe] Operand of null-aware operation '??' has type 'A' which excludes null.
//     ^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
  a ??= c;
//^
// [cfe] Operand of null-aware operation '??=' has type 'A' which excludes null.
//      ^
// [analyzer] STATIC_WARNING.DEAD_NULL_AWARE_EXPRESSION
  List<C> clist = [C(), C()];
  List<A> alist = [A(), C(), ...? clist];
  //                         ^^^^
  // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
  //                              ^
  // [cfe] Operand of null-aware operation '...?' has type 'List<C>' which excludes null.
}