Incorrect resolution with module paths and closure analysis

[aturon]

The following code incorrectly fails to compile:

use std::thread::spawn;

mod foo {
    struct Scope<'a>(&'a u8);
    pub fn scope<'a, F, R>(f: F) -> R where F: FnOnce(&Scope<'a>) -> R {
        panic!()
    }
}

fn main() {
    foo::scope(|scope| {
        spawn(move || {
            foo::scope(|s| {});
        });
    });
}

with error:

src/lib.rs:13:9: 13:14 error: the type `[closure@src/lib.rs:13:15: 15:10 scope:&foo::Scope<'_>]` does not fulfill the required lifetime [E0477]
src/lib.rs:13         spawn(move || {
                      ^~~~~
note: type must outlive the static lifetime

However, if you change the name scope in the closure within main, it works fine:

fn main() {
    foo::scope(|s| {
        spawn(move || {
            foo::scope(|s| {});
        });
    });
}

[nikomatsakis]

This is certainly creepy, nominating. Also I marked it as A-lifetimes because I don't think this impacts name resolution per se. My first thought is it is related to some of the known indeterminancies in region inference.

[aturon]

(This happens in 1.4 stable, 1.5 beta, and the 2015-10-31 nightly)

[aturon]

@nikomatsakis Note that the particular error here may be misleading. The original report was getting an error about Sync not being satisfied.

[nikomatsakis]

@aturon yes, I saw that, though it seems likely related

[arielb1]

Figured this out. Apparently resolve registers scope as an upvar. Will fix.