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Change-Id: Icb4eae77fab5257ea00ff948d3f775725398e6ab Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/142067 Commit-Queue: Bob Nystrom <rnystrom@google.com> Auto-Submit: Bob Nystrom <rnystrom@google.com> Reviewed-by: Erik Ernst <eernst@google.com>
30 lines
898 B
Dart
30 lines
898 B
Dart
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import "package:expect/expect.dart";
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typedef U F<T, U>(T x);
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class C<T> {
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T f(List<T> x) {
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throw "uncalled";
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}
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}
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F<List<num>, num> g(C<num> c) {
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return c.f;
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}
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void main() {
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var tearoff = g(new C<int>());
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// Since C.f's x parameter is covariant, its type is changed to Object when
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// determining the type of the tearoff. So the type of the tearoff should be
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// `(Object) -> int`. (Not, for example, `(List<Object>) -> int` or
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// `(List<Object>) -> Object`)
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Expect.isTrue(tearoff is F<Object, int>);
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// Because the function accepts any object, we can pass strings to it. This
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// will not work in Dart 1.
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Expect.isTrue(tearoff is F<String, int>);
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}
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