How to fix error[E0521]: borrowed data escapes outside of method?

help
1

Hi folks !

I need to fix the issue:

error[E0521]: borrowed data escapes outside of method
   --> src/main.rs:143:32
    |
131 | impl<'a> UI<'a> {
    |      -- lifetime `'a` defined here
...
140 |     fn handle_events(&mut self) -> JoinHandle<()> {
    |                      --------- `self` is a reference that is only valid in the method body
...
143 |         let characters_modal = Arc::clone(&self._characters_modal);
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |                                |
    |                                `self` escapes the method body here
    |                                argument requires that `'a` must outlive `'static`

I created a minimal sandbox example to reproduce this. Actually it's cropped version of my actual code.

Could somebody help on that to explain why this happens and how to fix this ? I believe "static" lifetime here is not a good choice and should be avoided.

2

spawn_blocking requires the 'static.

1 Like
3

Actually I am rewriting the part of my application and I used spawn_blocking before, but didn't set static lifetime. For example, here: tentacli/src/client/mod.rs at primary · idewave/tentacli · GitHub

How it works in that case ?

4

EventIncome has no lifetime (or type) parameters and thus satisfies a 'static bound; moreover you don't capture &mut self in the closure. Thus the closure satisifes a 'static bound.

1 Like
5

So, the only way to fix my issue is to set static lifetime for UI ?

6

Probably that, or have a method on all your lifetime-carrying structs that recursively drills down to the Cows and makes them Strings or Cow<'static, str>s on demand (within the method body).

Or find some framework that doesn't require 'static.

1 Like
7

Thank you very much for this hint ! I refactored the part of application where lifetimes were used and removed them. So now that error gone.

8

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