Tracking issue for boxed_slice_try_from

[dtolnay]

impl<T, const N: usize> TryFrom<Box<[T]>> for Box<[T; N]>
where
    [T; N]: LengthAtMost32;

impl<T, const N: usize> TryFrom<Rc<[T]>> for Rc<[T; N]>
where
    [T; N]: LengthAtMost32;

impl<T, const N: usize> TryFrom<Arc<[T]>> for Arc<[T; N]>
where
    [T; N]: LengthAtMost32;

These were added in #61515 with an #[unstable(...)] attribute but without a tracking issue. Since these are trait impls where both the trait and Self type are already stable, they are already callable on a stable compiler and we likely can't make further changes (other than removing the LengthAtMost32 bounds, which can take place after stabilization).

Anyone should feel free to send a "stabilization" PR changing the stability attributes to #[stable(...)].