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// 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.
// Requirements=nnbd-weak
// ddcOptions=--weak-null-safety-errors
import 'package:expect/expect.dart';
/// Code that runs without error when running with unsound null safety but
/// should throw in sound mode or when running DDC with
/// `--weak-null-safety-errors`.
void fn(StringBuffer arg) {}
void testArg<T>(T t) => throw 'do not call';
T testReturn<T>() => throw 'do not call';
const c = C<Duration>();
class C<T> {
covariantCheck(List<T> t) {}
const C();
}
void main() {
Expect.throwsTypeError(() => null as int);
dynamic dynamicNull = null;
Expect.throwsTypeError(() => fn(dynamicNull));
Expect.throwsTypeError(() => [Duration(days: 1), null] as List<Duration>);
// Constants get legacy types introduced in their type arguments.
C<Duration?> c2 = c;
Expect.throwsTypeError(() => c2.covariantCheck([Duration(days: 1), null]));
// Tearoff instantiations are "potentially constant" and are treated as a
// constant by the CFE.
// When compiling for unsound null safety the resulting type signature
// attached to the tearoff is `void Function(Duration*)` which is a valid
// subtype of `void Function(Duration?)`. In sound null safety the signature
// is `void Function(Duration)` which should fail in the cast.
Expect.throwsTypeError(() => (testArg<Duration>) as void Function(Duration?));
Expect.throwsTypeError(() => (testReturn<Duration?>) as Duration Function());
}