const indexing broken in nightly with bit shift (<<)

[Johnson-A]

const index: usize = 1;

fn main() {
    let array = [1,2,3];
    let test = 1 + array[index]; // This works fine
    let error = 1 << array[index]; // error: const indexing is an unstable feature
}

For some reason, indexing an array with a const requires an unstable feature when there is a bit shift operator. help: in Nightly builds, add #![feature(const_indexing)] to the crate attributes to enable. When adding the feature, there are no more errors but this feature shouldn't be necessary.

rustc 1.6.0-nightly (d49e365 2015-12-05)

[eddyb]

What's happening here is that there are const evaluations attempted to determine whether the shift is statically known to be overly long (array[index] >= 32, presumably), and that's hitting the const_indexing feature-gate without actually being in an explicit const context.
cc @oli-obk

[bluss]

This is the fix: #30202

[frewsxcv]

This can be closed?

[bluss]

Yep, the issue is fixed and has tests. Fixed in #30202.

[Johnson-A]

I still get the same compiler error using the latest nightly, however, it looks like the fix has already been merged

[mitaa]

On the current nightly, rustc --version outputs for me rustc 1.6.0-nightly (aad4e5665 2015-12-05)

This does not yet include the fix.

[oli-obk]

it was merged yesterday, so it should probably be in today's nightly (2015-12-08)