Summary

swap_with_temporary fires when you swap (the deref'd object behind) a MutexGuard with a stack variable as it incorrectly thinks the MutexGuard is a temporary.

Lint Name

swap_with_temporary

Reproducer

We have a bunch of cases like the following which now trigger the lint:

struct A { thing: Mutex<Vec<u8>>, } impl A { fn a(&self) { let new_vec = vec![42]; std::mem::swap(&mut self.thing.lock().unwrap(), new_vec); for v in new_vec { // Do something with v } }

Version

Additional Labels

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