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
57
|
// Regression test for #104005.
//
// Previously, different borrowck implementations used to disagree here.
// The status of each is documented on `fn test_*`.
//@ check-fail
use std::fmt::Display;
trait Displayable {
fn display(self) -> Box<dyn Display>;
}
impl<T: Display> Displayable for (T, Option<&'static T>) {
fn display(self) -> Box<dyn Display> {
Box::new(self.0)
}
}
fn extend_lt<T, U>(val: T) -> Box<dyn Display>
where
(T, Option<U>): Displayable,
{
Displayable::display((val, None))
}
// AST: fail
// HIR: pass
// MIR: pass
pub fn test_call<'a>(val: &'a str) {
extend_lt(val);
//~^ ERROR borrowed data escapes outside of function
}
// AST: fail
// HIR: fail
// MIR: pass
pub fn test_coercion<'a>() {
let _: fn(&'a str) -> _ = extend_lt;
//~^ ERROR lifetime may not live long enough
}
// AST: fail
// HIR: fail
// MIR: fail
pub fn test_arg() {
fn want<I, O>(_: I, _: impl Fn(I) -> O) {}
want(&String::new(), extend_lt);
//~^ ERROR temporary value dropped while borrowed
}
// An exploit of the unsoundness.
fn main() {
let val = extend_lt(&String::from("blah blah blah"));
//~^ ERROR temporary value dropped while borrowed
println!("{}", val);
}
|
