LanguageFeatures/nnbd/static_errors_A17_t04.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 not an error to call or tear-off a method, setter, or
/// getter, or to read or write a field, on a receiver of static type Never.
/// Implementations that provide feedback about dead or unreachable code are
/// encouraged to indicate that any arguments to the invocation are unreachable.
///
/// @description Check that it is a warning to call a method, setter, or
/// getter on a receiver of static type Never via a null aware operator. Test
/// type aliases
/// @author sgrekhov@unipro.ru
/// @issue 39866

// Requirements=nnbd-strong
typedef Neverland = Never;

void test(var x) {
  if (x is Neverland) {
    x?.toString();
//   ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//  ^
// [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
    x?.runtimeType;
//   ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//  ^
// [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
    x?.s = 1;
//   ^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//  ^
// [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
    x?..toString();
//   ^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//  ^
// [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
    x?..runtimeType;
//   ^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//  ^
// [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
    x?..s = 1;
//   ^^^
// [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
//  ^
// [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
  }
}

main() {
  test(null);
}