&[1, 2, 3] should always be &'static [<generic integer>]

[thestinger]

The following works:

fn foo<'a>(xs: &'a [int]) -> &'a [int] {
    if xs.len() & 1 == 0 {
        static ys: &'static [int] = &[1, 2, 3];
        ys
    } else {
        xs
    }
}

This should also work, but does not:

fn foo<'a>(xs: &'a [int]) -> &'a [int] {
    if xs.len() & 1 == 0 {
        &[1, 2, 3]
    } else {
        xs
    }
}

[nikomatsakis]

cc me

[steveklabnik]

I'm pulling a massive triage effort to get us ready for 1.0. As part of this, I'm moving stuff that's wishlist-like to the RFCs repo, as that's where major new things should get discussed/prioritized.

This issue has been moved to the RFCs repo: rust-lang/rfcs#827

[thestinger]

This isn't a proposal for a language change, it's a bug report.

[steveklabnik]

We had an IRC chat about it, and it seems to me like an enhancement. Changing &[1, 2, 3] to go from "a reference to a stack allocated array" to "a statically allocated array" seems like a semantic change, no?

[thestinger]

The fact that the compiler is treating immutable constant expressions as stack allocations is a bug. There is no language change to discuss here, only an implementation improvement.