Stream: git-wasmtime

Topic: wasmtime / issue #12588 [QUESTION] Is it mandatory in `li...

Wasmtime GitHub notifications bot (Feb 13 2026 at 09:56):

if0ne opened issue #12588:

Hi there!

I want to do something like this:

store.limiter_async(move |_| &mut memory_limiter);

The memory limiter is created and configured outside of the store creation.

However, this is currently impossible:

store.limiter_async(move |_| &mut memory_limiter);
    |                                     -------- ^^^^^^^^^^^^^^^^^^^ closure was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
    |                                     |     |
    |                                     |     has type `&'2 mut SharedCtx`
    |                                     lifetime `'1` represents this closure's body
    |
    = note: closure implements `FnMut`, so references to captured variables can't escape the closure

Should I move the limiter into the store’s data, or is this something that could be fixed in future releases?

Wasmtime GitHub notifications bot (Feb 13 2026 at 15:54):

alexcrichton commented on issue #12588:

Yes for now you'll need to place the limiter in the store's data itself, as Rust's closures don't allow this style of borrowing where you return a borrow of the captured data itself. As for fixing this and/or supporting this, it's in theory possible yeah and would likely require adjusting bounds here. For now does moving into the store work for you?

Wasmtime GitHub notifications bot (Feb 13 2026 at 18:39):

if0ne commented on issue #12588:

Yes, moving the limiter into the Store works fine for me. Thanks you

Wasmtime GitHub notifications bot (Feb 14 2026 at 21:23):

alexcrichton closed issue #12588:

Hi there!

I want to do something like this:

store.limiter_async(move |_| &mut memory_limiter);

The memory limiter is created and configured outside of the store creation.

However, this is currently impossible:

store.limiter_async(move |_| &mut memory_limiter);
    |                                     -------- ^^^^^^^^^^^^^^^^^^^ closure was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1`
    |                                     |     |
    |                                     |     has type `&'2 mut SharedCtx`
    |                                     lifetime `'1` represents this closure's body
    |
    = note: closure implements `FnMut`, so references to captured variables can't escape the closure

Should I move the limiter into the store’s data, or is this something that could be fixed in future releases?

Wasmtime GitHub notifications bot (Feb 14 2026 at 21:23):

alexcrichton commented on issue #12588:

Ok great! In that case I'll close this for now, but if that becomes problematic I can also reopen for a future feature to update the siganture of this function.

Last updated: Feb 24 2026 at 04:36 UTC