File: gat-bounds-not-checked-with-right-substitutions.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 (29 lines) | stat: -rw-r--r-- 628 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
// This test checks that we correctly reject the following unsound code.

trait Lengthen<T> {
    fn lengthen(self) -> T;
}

impl<'a> Lengthen<&'a str> for &'a str {
    fn lengthen(self) -> &'a str { self }
}

trait Gat {
    type Gat<'a>: for<'b> Lengthen<Self::Gat<'b>>;

    fn lengthen(s: Self::Gat<'_>) -> Self::Gat<'static> {
        s.lengthen()
    }
}

impl Gat for () {
    type Gat<'a> = &'a str; //~ ERROR: implementation of `Lengthen` is not general enough
}

fn main() {
    let s = "hello, garbage".to_string();
    let borrow: &'static str = <() as Gat>::lengthen(&s);
    drop(s);

    println!("{borrow}");
}