ICE: mir build: scope: `index out of bounds: the len is 0 but the index is 0` about rust HOT 6 OPEN

These examples all generate correct errors on beta (which contains inline const stablisation) but ICE on nightly. Looks like something else breaks these?

from rust.

Minimized:

fn foo() {
    const { return }
}

Variations that also cause ICEs of varying kinds:

fn foo() {
    'a: {
        const { break 'a }
    }
}

fn foo() {
    loop {
        const { break }
    }
}

fn foo() {
    'a: {
        const { continue 'a }
    }
}

fn foo() {
    loop {
        const { continue }
    }
}

async fn foo() {
    const { async {}.await }
}

fn foo() {
    let x = 1;
    const { &x };
}

from rust.

cc @nbdd0121 that's pretty bad... the fix for that should probably be backported or maybe even delaying the stabilization for one release? no strong opinion.

from rust.

@rustbot label: +E-needs-bisection

from rust.

I've tried bisecting a couple of them and they all both point to 7717a30 cc @oli-obk @nnethercote

@rustbot label -E-needs-bisection

from rust.

WG-prioritization assigning priority (Zulip discussion).

Being easy to be triggered even if for now only on nightly.

@rustbot label -I-prioritize +P-high

from rust.