Make LocalWaker::new a const fn #53456
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| /// on the current thread. | ||
| #[inline] | ||
| pub unsafe fn new(inner: NonNull<dyn UnsafeWake>) -> Self { | ||
| pub const unsafe fn new(inner: NonNull<dyn UnsafeWake>) -> Self { |
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Please add the rustc_const_unstable attribute and a test enabling the feature and using it.
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See #47562 for an example.
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Yep, I managed to get an example going. Unfortunately writing that example made me realise that this isn't usable for what I want anyway since it's !Send + !Sync so can't go in a static, as I don't know of any other usecases for this to be const I'm gonna close this and try to find an alternative.
One thing I noticed while adding the example, rustc_const_unstable requires a stable/unstable directly on the item being annotated, LocalWaker is in an unstable module so doesn't have a direct annotation, is there some reason the attribute needs to be directly on the item instead of inheriting from its parent scope?
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Is there some reason the attribute needs to be directly on the item instead of inheriting from its parent scope?
Does implementation lazyness count as a reason?
Most newly added const fns already had a stability attribute, so it was less hazzle to add an attribute to those that didn't have it than to correctly implement the attribute
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Implementation lazyness is the best reason.
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<Joke about Haskell has been elided due to laziness>
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This is mostly not that useful, except for
futures-testwhere we want to have statics available for the more trivial test wakers for better ergonomics.r? @cramertj