42 lines
1.2 KiB
Rust
42 lines
1.2 KiB
Rust
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// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Test for RFC 1268: we allow overlapping impls of marker traits,
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// that is, traits without items. In this case, a type `T` is
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// `MyMarker` if it is either `Debug` or `Display`. This test just
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// checks that we don't consider **all** types to be `MyMarker`. See
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// also the companion test in
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// `run-pass/overlap-permitted-for-marker-traits.rs`.
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#![feature(overlapping_marker_traits)]
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#![feature(optin_builtin_traits)]
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use std::fmt::{Debug, Display};
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trait Marker {}
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impl<T: Debug> Marker for T {}
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impl<T: Display> Marker for T {}
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fn is_marker<T: Marker>() { }
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struct NotDebugOrDisplay;
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fn main() {
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// Debug && Display:
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is_marker::<i32>();
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// Debug && !Display:
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is_marker::<Vec<i32>>();
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// !Debug && !Display
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is_marker::<NotDebugOrDisplay>(); //~ ERROR
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}
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