Tracking Issue for separate array length function

[shamatar]

Feature gate: #![feature(array_len)]

This is a tracking issue for a separate length function on arrays (without coercing into slice and calling slice::len). It allows to lower array length access into constant in MIR without any additional modifications.

Public API

// core::array

impl<T, const N: usize> [T; N] {
    #[inline]
    pub const fn len(&self) -> usize {
        N
    }

Steps / History

• Implementation: Add separate array length function #86404
• Final commenting period (FCP)
• Stabilization PR

Unresolved Questions

None so far

[shamatar]

As pointed in the implementation PR it's breaking if it's not immediately stable, but if it is then current machinery is ok with resolving a proper one

[m-ou-se]

Closing this for now, because we still need to figure out if we want this addition.

(And if we do, it'd have to be insta-stable, so then there'd be no unstable feature to track anyway.)