issue-25860 spike

[nikomatsakis]

The goal of this spike is to get this program checking completely within a-mir-formality:

static UNIT: &'static &'static () = &&();

fn foo<'a, 'b, T>(_: &'a &'b (), v: &'b T) -> &'a T {
    v
}

fn bad<'a, T>(x: &'a T) -> &'static T {
    let f: fn(_, &'a T) -> &'static T = foo;
    f(UNIT, x)
}

fn main() {
    let value = {
        let data = 22;
        bad(&data)
    };
    let _ = *value;
}

Subgoals:

• [ ] #25
• [ ] #23
• [ ] #54
• [x] #24
• [ ] #55
• [ ] #26
• [ ] #28
• [ ] #30
• [ ] #29