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Spurious "borrowed value does not live long enough" when calling a function through a function pointer #49073
Description
The following code (edited to an even smaller version provided by occultus):
use std::string::ToString;
fn main() {
let to_string = ToString::to_string;
let i = 1;
let b = &i;
assert_eq!("", to_string(&b));
}yields the following compiler output:
error[E0597]: `i` does not live long enough
--> src/main.rs:6:14
|
6 | let b = &i;
| ^ borrowed value does not live long enough
7 | assert_eq!("", to_string(&b));
8 | }
| - `i` dropped here while still borrowed
|
= note: values in a scope are dropped in the opposite order they are created
Moving let to_string down one line "fixes" it. So does #![feature(nll)].
In case you wonder how one ends up with code like this, it's because this is test code, and to_string is actually <Trait as ToString>::to_string, which is a lot of boilerplate.
Activity
durka commentedon Mar 16, 2018
For bonus points, try annotating the type of
to_string.hanna-kruppe commentedon Mar 16, 2018
Apparently the code was edited, but the error message was updated to the new code? Very confusing!
glandium commentedon Mar 16, 2018
Sorry, I forgot to update the line numbers. Fixed.
memoryruins commentedon Jan 30, 2019
Triage: now compiles on 2018 edition.
2015 errors:
rustc: 1.32.0Auto merge of #59114 - matthewjasper:enable-migate-2015, r=<try>
Auto merge of #59114 - matthewjasper:enable-migate-2015, r=pnkfelix
Auto merge of #59114 - matthewjasper:enable-migate-2015, r=pnkfelix