In Rust, you can convert a slice &[T] to an array [T; N] using <[T; N] as TryFrom<&[T]>>::try_from. The main issue with this is that it depends on a trait function, and trait functions are not allowed in constant expressions (e.g. const fn).
I propose adding a try_from_slice function to the core::array module for this scenario. The module in question already defines other constructors such as from_fn and from_ref.
The following function should be added to the standard library:
// core::array
pub const fn try_from_slice<T, const N: usize>(slice: &[T]) -> Result<[T; N], TryFromSliceError>
where
T: Copy; Alternatives
The main alternative to adding this feature (with regard to const) would be to allow trait functions in constant expressions. This is already covered by const_trait_impl.
I still do believe adding this function can improve clarity in some code. Other areas of the standard library already define similar patterns, e.g. String implements Into<Box<str>> whilst also defining the into_boxed_str destructor.
Initial, unstable implementation: #133439
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