[ICE]: llvm error: `ResumeInst needs to be in a function with a personality`

[matthiaskrgr]

auto-reduced (treereduce-rust):

//@compile-flags: -Zmir-opt-level=0 -Zverify-llvm-ir=yes -Clink-dead-code=true
use std::ops::Deref;
trait Foo {
    fn method(&self) {}
}
impl Foo for u32 {}

fn via_deref_nested() -> Box<impl Deref<Target = impl Foo>> {
    if false {
        via_deref_nested().method();
    }

    Box::new(Box::new(1u32))
}

fn main() {}

original:

//! The recursive method call yields the opaque type. We want
//! to use the trait candidate for `impl Foo` here while not
//! applying it for the `impl Deref`.

//@ revisions: current next
//@[next] compile-flags: -Znext-solver
//@ check-pass

use std::ops::Deref;
trait Foo {
    fn method(&self) {}
}
impl Foo for u32 {}
fn via_deref() -> impl Deref<Target = impl Foo> {
    if false {
        if false {
        via_deref_nested().method();
    }
    }

    Box::new(1u32)
}

fn via_deref_nested() -> Box<impl Deref<Target = impl Foo>> {
    if false {
        via_deref_nested().method();
    }

    Box::new(Box::new(1u32))
}

fn main() {}

Version information

rustc 1.99.0-nightly (5d4886964 2026-07-26)
binary: rustc
commit-hash: 5d4886964b04e1aa6aca158a677183a778e2950d
commit-date: 2026-07-26
host: x86_64-unknown-linux-gnu
release: 1.99.0-nightly
LLVM version: 22.1.8

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zmir-opt-level=0 -Zverify-llvm-ir=yes -Clink-dead-code=true

Program output

warning: trait `Foo` is never used
 --> /tmp/icemaker_global_tempdir.rPGSLcie4PU1/rustc_testrunner_tmpdir_reporting.qXYPqbNhVFid/mvce.rs:2:7
  |
2 | trait Foo {
  |       ^^^
  |
  = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default

warning: function `via_deref_nested` is never used
 --> /tmp/icemaker_global_tempdir.rPGSLcie4PU1/rustc_testrunner_tmpdir_reporting.qXYPqbNhVFid/mvce.rs:7:4
  |
7 | fn via_deref_nested() -> Box<impl Deref<Target = impl Foo>> {
  |    ^^^^^^^^^^^^^^^^

ResumeInst needs to be in a function with a personality.
  resume { ptr, i32 } %12
rustc-LLVM ERROR: Broken module found, compilation aborted!

[matthiaskrgr]

bisects to #143208

[matthiaskrgr]

//@compile-flags: -Zmir-opt-level=0 -Zverify-llvm-ir=yes
use std::ops::Deref;

trait Foo {
    fn method(&self) {}
}

impl Foo for u32 {}

fn via_deref_nested() -> Box<impl Deref<Target = impl Foo>> {
    if false {
        via_deref_nested().method();
    }

    Box::new(Box::new(1u32))
}

fn main() {
    via_deref_nested();
}

this way we don't need Clink-dead-code