blob: 7f1b3f9fbe76daf7ca1e721540e468f0196cea2a [file] [log] [blame]
// Copyright (c) 2020, 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 definitions of least and greatest closure are changed in null
/// safe libraries to substitute [Never] in positions where previously [Null
/// would have been substituted, and [Object?] in positions where previously
/// [Object] or [dynamic] would have been substituted.
/// @description Check that [Object?] type is substituted for [typedef C<X> =
/// A<X>].
/// @note Read more about the least and greatest closure test template:
/// @Issue 42580
/// @author
import "../../../../Utils/expect.dart";
abstract class A<X> {
X get x;
set x(X value);
typedef C<X> = A<X>;
void main() {
void f<X>(C<X> Function() g) => g();
// Verify that the captured type has an `x`.
f(() => captureTypeArgument()..x);
// Verify that `x` has a top type.
f(() => captureTypeArgument()..x = 42);
f(() => captureTypeArgument()..x = 'Hello');
f(() => captureTypeArgument()..x = null);
// Verify that `x` does not have type `dynamic` (but, expecting the type
// to be `Object?` we need the null aware access `?.`).
f(() => captureTypeArgument()..x?.unknownMember);
// ^
// [analyzer] unspecified
// [cfe] unspecified
// Verify that `x` has `Object` members (so it can have type `Object?`,
// but it cannot have type `void`).
f(() => captureTypeArgument()..x.toString);