Tracking Issue for future::lazy

[ibraheemdev]

Feature gate: #![feature(future_lazy)]

This is a tracking issue for core::future::{lazy, Lazy}, which executes a closure the first time it is polled:

let a = std::future::lazy(|_| 1);
assert_eq!(a.await, 1);

Public API

// core::future

pub struct Lazy<F> {
    f: Option<F>,
}

pub fn lazy<F, R>(f: F) -> Lazy<F>
where
    F: FnOnce(&mut Context<'_>) -> R,
{
    // ..
}

impl<F, R> Future for Lazy<F>
where
    F: FnOnce(&mut Context<'_>) -> R,
{
    type Output = R;

    // ...
}

Steps / History

• Implementation: Implement core::future::lazy #91648
• Final comment period (FCP)
• Stabilization PR

Unresolved Questions

• None yet.

[ibraheemdev]

Closing per #91648 (comment).