const in array types causes rustc error

[tjhance]

Reported on zulip:

const TEST: usize = 4;

pub fn get_array() -> [u8; TEST] {
    return [0; TEST]
}

gives this error:

error[E0080]: it is undefined behavior to use this value
 --> txz.rs:4:28
  |
4 | pub fn get_array() -> [u8; TEST] {
  |                            ^^^^ constructing invalid value: encountered uninitialized memory, but expected an integer

I'm pretty sure this has to do with the override of providers.eval_to_const_value_raw in the recent 1.79.0 upgrade.

[tjhance]

This is also problematic because the issue isn't restricted to the verus! macro, so it's problematic for crates with lots of external code. Currently a blocking issue for the rustlib project.