tests/ui/traits/const-traits/const-impl-trait.rs


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

//@ check-pass
//@ compile-flags: -Znext-solver

#![allow(incomplete_features)]
#![feature(const_trait_impl, const_cmp, const_destruct)]

use std::marker::Destruct;

const fn cmp(a: &impl [const] PartialEq) -> bool {
    a == a
}

const fn wrap(
    x: impl [const] PartialEq + [const] Destruct,
) -> impl [const] PartialEq + [const] Destruct {
    x
}

#[const_trait]
trait Foo {
    fn huh() -> impl [const] PartialEq + [const] Destruct + Copy;
}

impl const Foo for () {
    fn huh() -> impl [const] PartialEq + [const] Destruct + Copy {
        123
    }
}

const _: () = {
    assert!(cmp(&0xDEADBEEFu32));
    assert!(cmp(&()));
    assert!(wrap(123) == wrap(123));
    assert!(wrap(123) != wrap(456));
    let x = <() as Foo>::huh();
    assert!(x == x);
};

#[const_trait]
trait T {}
struct S;
impl const T for S {}

const fn rpit() -> impl [const] T {
    S
}

const fn apit(_: impl [const] T + [const] Destruct) {}

const fn rpit_assoc_bound() -> impl IntoIterator<Item: [const] T> {
    Some(S)
}

const fn apit_assoc_bound(_: impl IntoIterator<Item: [const] T> + [const] Destruct) {}

fn main() {}