Make `array::{try_from_fn, try_map}` and `Iterator::try_find` generic over `Try` by scottmcm · Pull Request #91286 · rust-lang/rust (original) (raw)

bors added a commit to rust-lang-ci/rust that referenced this pull request

…ttmcm

Stabilize array_from_fn

Overall

Stabilizes core::array::from_fn ~~and core::array::try_from_fn~~ to allow the creation of custom infallible ~~and fallible~~ arrays.

Signature proposed for stabilization here, tweaked as requested in the meeting:

// in core::array

pub fn from_fn<T, const N: usize, F>(_: F) -> [T; N];

On 2020-08-17, implementation was proposed.
On 2021-09-29, tracking issue was created.
On 2021-10-09, the proposed implementation was merged.
On 2021-12-03, the return type of try_from_fn was [changed](rust-lang#91286 (comment)).

It is being assumed that indices are useful and shouldn't be removed from the callbacks
The fact that try_from_fn returns an unstable type R: Try does not prevent stabilization. Although I'm honestly not sure about it.
The addition or not of repeat-like variants is orthogonal to this PR.

These considerations are not ways of saying what is better or what is worse. In reality, they are an attempt to move things forward, anything really.