Can create `&mut` with only `&` in statics

[huonw]

This compiles fine:

#![allow(dead_code)]

static FOO: [uint, .. 2] = [0, 0];
static BAR: &'static mut [uint, .. 2] = & FOO;

fn main() {}

[nikomatsakis]

What the !@#!@#!@

[pnkfelix]

very weird, seems highly misleading... but ... also not a high priority to fix, since one cannot actually write through *BAR, nor does it work if FOO is static mut.

So, P-high, not 1.0.

[pythonesque]

@pnkfelix True, but you can still get aliased &muts through it quite easily, which you're not supposed to be able to do in safe code. I agree it's a weird situation.

[nham]

This seems to be fixed in the current nightly. The updated code is

static FOO: [usize; 2] = [0, 0];
static BAR: &'static mut [usize; 2] = & FOO;

fn main() {}

It does not compile:

test_18939.rs:2:39: 2:44 error: mismatched types:
 expected `&'static mut [usize; 2]`,
    found `&[usize; 2]`
(values differ in mutability) [E0308]
test_18939.rs:2 static BAR: &'static mut [usize; 2] = & FOO;
                                                      ^~~~~
error: aborting due to previous error

rustc version:

rustc 1.1.0-nightly (435622028 2015-05-04) (built 2015-05-05)

[steveklabnik]

Thanks @nham !