attributes: force instrumented function to be `FnOnce`

tokio-rs / tracing

Application level tracing for Rust.

https://tracing.rs

MIT License

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Closed mladedav closed 4 months ago

mladedav commented 5 months ago

Closes #2857

Functions which are Fn or FnMut fail to compile when they are instrumented with #[instrument(ret)]

I've added a non-copy zst ([&mut (), 0]) to the generated code that is moved inside the function so that it is forced to be no more than FnOnce.

mladedav commented 4 months ago

I've created #2897 to be merged into master and then backported to v0.1.x since that's the workflow here.