ICE for vec.iter() with unbounded element type

[huonw]

fn main() {
    let v = &[];
    let it = v.iter();
}

vec-ice.rs:3:13: 3:14 error: internal compiler error: borrow-vec associated with bad sty: &ty_err
vec-ice.rs:3     let it = v.iter();
                          ^

(Doesn't happen with .slice.)

[jdm]

Paging @catamorphism!

[chris-morgan]

Here's a truly minimal test case:

fn main() { [].iter(); }

[nikomatsakis]

cc me

[michaelwoerister]

Variation:

fn main() { [&1].iter(); }

This gives a different error message:

error: internal compiler error: Cannot relate bound region: ReInfer(2) <= ReLateBound(161, BrNamed(syntax::ast::DefId{crate: 0u32, node: 174u32}, a))

Fixed in #16802. Can be closed.