In case the wording tripped anyone, generators (blocks and functions) have been available for a while as an unstable feature.

This works (playground):

#![feature(gen_blocks)]

gen fn gfn() -> i32 {
    for i in 1..=10 {
        yield i;
    }
}

fn gblock() -> impl Iterator {
    gen {
        for i in 1..=10 {
            yield i;
        }
    }
}

fn main() {
    for i in gfn() {
        println!("{i} from gfn()");
    }
    for i in gblock() {
        println!("{i} from gblock()");
    }
}

Note that the block-in-fn version works better at this moment (from a developer’s PoV) because rust-analyzer currently treats gfn() as an i32 value. But the block-in-fn pattern works perfectly already.

It was mentioned in the notes for 1.84.0 that they began migrating to it. They might be doing it without an edition change if it’s backwards compatible (or if the incompatibilities are considered bugs).

Road to 2027 then?