Clippy crashes on simple method returning `impl PartialOrd`

[djkoloski]

Summary

This is probably caused by #9733 per a crash analysis:

...
#30580 0x0000555c0ff6ebc0 in clippy_utils::ty::contains_ty_adt_constructor_opaque ()
#30581 0x0000555c0ff6ebc0 in clippy_utils::ty::contains_ty_adt_constructor_opaque ()
#30582 0x0000555c0ff6ebc0 in clippy_utils::ty::contains_ty_adt_constructor_opaque ()
#30583 0x0000555c0ff6ebc0 in clippy_utils::ty::contains_ty_adt_constructor_opaque ()
#30584 0x0000555c0fcbb240 in <clippy_lints::methods::Methods as rustc_lint::passes::LateLintPass>::check_impl_item ()
#30585 0x00007fe4894426dd in rustc_hir::intravisit::walk_item::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>> ()
...

Reproducer

I tried this code:

pub struct Bomb;

impl Bomb {
    pub fn explode(&self) -> impl PartialOrd {
        0i32
    }
}

I expected to see this happen:

Clippy does not crash.

Instead, this happened:

Clippy crashes with a stack overflow exception.

Version

rustc 1.65.0 (897e37553 2022-11-02)
binary: rustc
commit-hash: 897e37553bba8b42751c67658967889d11ecd120
commit-date: 2022-11-02
host: x86_64-unknown-linux-gnu
release: 1.65.0
LLVM version: 15.0.0

Additional Labels

No response

[djkoloski]

We believe that this is because PartialOrd has a generic parameter RHS = Self which causes this check to recurse on Self, which is once again PartialOrd<RHS = Self>.

[matthiaskrgr]

Nominating for the next meeting; is this something we want to fix and beta backport? As far as I understand this will make it into the imminent master -> beta promition.

[nbdd0121]

Sorry for the trouble, just saw this today (as I wasn't cc'ed in this issue).

Yes your analysis is correct, this is caused by recursive Self which is again the same opaque type.