File: never-value-fallback-issue-66757.rs

package info (click to toggle)
rustc-web 1.78.0%2Bdfsg1-2~deb12u3
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 1,245,420 kB
  • sloc: xml: 147,985; javascript: 18,022; sh: 11,083; python: 10,265; ansic: 6,172; cpp: 5,023; asm: 4,390; makefile: 4,269
file content (31 lines) | stat: -rw-r--r-- 704 bytes parent folder | download | duplicates (6)
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
// Regression test for #66757
//
// Test than when you have a `!` value (e.g., the local variable
// never) and an uninferred variable (here the argument to `From`) it
// doesn't fallback to `()` but rather `!`.
//
//@ revisions: nofallback fallback
//@[fallback] run-pass
//@[nofallback] check-fail

#![feature(never_type)]

#![cfg_attr(fallback, feature(never_type_fallback))]

struct E;

impl From<!> for E {
    fn from(_: !) -> E {
        E
    }
}

#[allow(unreachable_code)]
#[allow(dead_code)]
#[allow(unused_must_use)]
fn foo(never: !) {
    <E as From<!>>::from(never);  // Ok
    <E as From<_>>::from(never);  //[nofallback]~ ERROR trait bound `E: From<()>` is not satisfied
}

fn main() { }