Hang / High CPU usage with `tracing` macros

[SludgePhD]

rust-analyzer version: 0.3.2253-standalone

rustc version: rustc 1.83.0 (90b35a623 2024-11-26)

editor or extension: VS Code

relevant settings: none

code snippet to reproduce:

fn main() {
    tracing::error!()
}

This snippet causes rust-analyzer to take 100% of one CPU for several dozen seconds. It is completely unresponsive during that time, so this is making it pretty hard to use.

This is with tracing = "0.1.41".

[Veykril]

Hmm, the only relevant thing I can think of would be the token tree changes

[ChayimFriedman2]

So the trigger was indeed my PR. I found out what happen, and this is... both happy and makes me want to cry. At least I can say the error is not mine, it was pre-existing. More details to come :)