Stabilise inline_const by nbdd0121 · Pull Request #104087 · rust-lang/rust
github.com
Stabilisation Report Summary This PR will stabilise inline_const feature in expression position. inline_const_pat is still unstable and will not be stabilised. The feature will allow code like this...
  • sugar_in_your_tea@sh.itjust.works
    0·
    5 months ago

    Huh, this is awesome! From the link, this now works:

    let v: Vec<i32> = const { Vec::new() };

    I’m going to have to play with this to see how far it goes.

      • sugar_in_your_tea@sh.itjust.works
        2·
        5 months ago

        Ah, apparently for now you’re not allowed to allocate. But vec::new_in(allocator) looks interesting. This works in nightly today:

        #![feature(allocator_api)]

use std::alloc::Global;

fn main() {
    const MY_VEC: Vec<i32> = const {
        Vec::new_in(Global)
    };
    println!("{:?}", MY_VEC);
}

        Maybe at some point I can append to it at compile time too. I’d love to be able to put a const {} and have allocations that resolve down to a 'static, and this seems to be a step toward that.

        I guess I’m just excited that Vec::new() is the example they picked, since the next obvious question is, “can I push?”