aaefa947ac
Note that this commit, since it is trying to be minimal in order to ease backporting to the beta and release channels, does *not* include the old future-proofing warnings that we used to have associated with such fallback to `()`; see discussion at this comment: https://github.com/rust-lang/rust/issues/49691#issuecomment-381266730
45 lines
1.2 KiB
Rust
45 lines
1.2 KiB
Rust
// Copyright 2016 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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// We need to opt inot the `!` feature in order to trigger the
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// requirement that this is testing.
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#![feature(never_type)]
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#![allow(unused)]
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trait Deserialize: Sized {
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fn deserialize() -> Result<Self, String>;
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}
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impl Deserialize for () {
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fn deserialize() -> Result<(), String> {
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Ok(())
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}
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}
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trait ImplementedForUnitButNotNever {}
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impl ImplementedForUnitButNotNever for () {}
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fn foo<T: ImplementedForUnitButNotNever>(_t: T) {}
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//~^ NOTE required by `foo`
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fn smeg() {
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let _x = return;
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foo(_x);
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//~^ ERROR the trait bound
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//~| NOTE the trait `ImplementedForUnitButNotNever` is not implemented
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//~| NOTE the trait is implemented for `()`
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}
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fn main() {
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smeg();
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}
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