File: unused-closure.rs

package info (click to toggle)
rustc 1.88.0%2Bdfsg1-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 934,128 kB
  • sloc: xml: 158,127; python: 36,062; javascript: 19,855; sh: 19,700; cpp: 18,947; ansic: 12,993; asm: 4,792; makefile: 690; lisp: 29; perl: 29; ruby: 19; sql: 11
file content (34 lines) | stat: -rw-r--r-- 852 bytes parent folder | download | duplicates (15)
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
// Test that closures and coroutines are "must use" types.
//@ edition:2018

#![feature(coroutines, stmt_expr_attributes)]
#![deny(unused_must_use)]

fn unused() {
    || { //~ ERROR unused closure that must be used
        println!("Hello!");
    };

    async {};    //~ ERROR unused implementer of `Future` that must be used
    || async {}; //~ ERROR unused closure that must be used
    async || {}; //~ ERROR unused closure that must be used


    [Box::new([|| {}; 10]); 1]; //~ ERROR unused array of boxed arrays of closures that must be used

    vec![|| "a"].pop().unwrap(); //~ ERROR unused closure that must be used

    let b = false;
        || true; //~ ERROR unused closure that must be used
    println!("{}", b);
}

fn ignored() {
    let _ = || {};
    let _ = #[coroutine] || yield 42;
}

fn main() {
    unused();
    ignored();
}