Hang in item-bodies checking when dependency contains `pub use crate`

[dtolnay]

Compiling the following pair of crates hangs and chews up memory.

src/main.rs

fn main() {
    repro_dep::S.f();
}

dep/src/lib.rs

pub use crate as krate;
pub struct S;

---

Repro script:

#!/bin/bash

cargo new --bin repro
cargo new --lib repro-dep

echo >repro/src/main.rs '
fn main() {
    repro_dep::S.f();
}
'

echo >>repro/Cargo.toml '
repro-dep = { path = "../repro-dep" }
'

echo >repro-dep/src/lib.rs '
pub use crate as krate;
pub struct S;
'

cargo rustc --manifest-path repro/Cargo.toml -- -Ztime-passes

---

Mentioning @petrochenkov and @nikomatsakis who worked on #45477. Mentioning @nrc who hit this in a real project.

[jonas-schievink]

https://github.com/rust-lang/rust/issues/57500 is similar, so this might be a duplicate

[petrochenkov]

Same as https://github.com/rust-lang/rust/issues/55779, most probably.

[dtolnay]

Thanks, closing as a duplicate of #57500. #55779 seems somewhat different because it manifests as a compile time stack overflow rather than hang, but it is possible they will be addressed by the same fix.