stack overflow in nursery lints

[matthiaskrgr]

Summary

.

Reproducer

I tried this code:
clippy-driver -Wclippy::nursery

//@ check-pass

#[derive(Debug)]
struct S<T> {
    t: T,
    s: Box<S<fn(u: T)>>,
}

fn main() {}

warning: struct `S` is never constructed
 --> ./src/tools/clippy/tests/ui/crashes/ice-10508c.rs:4:8
  |
4 | struct S<T> {
  |        ^
  |
  = note: `#[warn(dead_code)]` on by default


thread 'rustc' has overflowed its stack
fatal runtime error: stack overflow
Aborted (core dumped)

Version

rustc 1.87.0-nightly (351686bcf 2025-03-01)
binary: rustc
commit-hash: 351686bcfd18dd0f652aba69a806bfa68c57234d
commit-date: 2025-03-01
host: x86_64-unknown-linux-gnu
release: 1.87.0-nightly
LLVM version: 20.1.0

Additional Labels

No response

[lapla-cogito]

This is occurring in significant_drop_tightning (checked with clippy-driver -Wclippy::significant_drop_tightening src/main.rs). I'll look closer.

[y21]

Probably the same issue as #13544.

[y21]

This was fixed by #14641 (along with #13544, which indeed this was a duplicate of and had the same backtrace)