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Gavin-Niederman
requested changes
Oct 30, 2024
| unsafe impl<T: ?Sized + Send> Send for Mutex<T> {} | ||
| unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {} | ||
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| impl<T> Mutex<T> { |
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If you cannot use Mutex::new if T is unsized, how is this relaxed Size bound useful?
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github kinda threw, the line im talking about is 93
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Mutexes can be coerced into an unsized type after creation, delegating the bound on Sized to a wrapper type like Arc. This is useful for trait objects - for example:
use std::sync::*;
use std::any::Any;
fn main() {
let x: Arc<Mutex<dyn Any>> = Arc::new(Mutex::new(3));
}Would avoid the additional heap allocation of an Arc<Mutex<Box<dyn Any>>>
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Describe the changes this PR makes. Why should it be merged?
Makes
TonMutex<T>?Sized, relaxing the requirement thatThave a known size at compile time. This matches the behavior of the standard library.I think this is a breaking change? (although it shouldn't affect the vast majority of people)