Cycle detected when optimizing MIR #146998
Description
Code
I tried this code:
https://github.com/FlixCoder/fhir-sdk
cargo build -p fhir-model --release(Probably the same as creating a crate with dependency fhir-model from crates.io).
The example crate is huge and difficult to navigate, so I tried to reproduce with a minimal example with the same cycle:
#[derive(Debug, PartialEq)]
pub struct Bundle(pub Box<BundleInner>);
#[derive(Debug, PartialEq)]
pub struct BundleInner {
pub issues: Option<Resource>,
pub entry: Vec<Option<BundleEntry>>,
}
#[derive(Debug, PartialEq)]
pub struct BundleEntry {
pub resource: Option<Resource>,
}
#[derive(Debug, PartialEq)]
pub enum Resource {
Bundle(Bundle),
}However, this successfully compiles.. So I don't really know how to proceed from here, I am open to suggestions what we could try to find a better small example.
I expected to see this happen: Code compiles with opt-level > 1
Instead, this happened: Compilation error on opt-level > 1
(See FlixCoder/fhir-sdk#56 )
Version it worked on
It most recently worked on: 1.89
Version with regression
Rust 1.90 does not and rustc 1.92.0-nightly (975e6c8 2025-09-23) also does not work.
rustc --version --verbose:
rustc 1.92.0-nightly (975e6c8fe 2025-09-23)
binary: rustc
commit-hash: 975e6c8fec280816d24fbde6b8dfe19620f2efe6
commit-date: 2025-09-23
host: x86_64-unknown-linux-gnu
release: 1.92.0-nightly
LLVM version: 21.1.1
Backtrace
Backtrace
No crash, no backtrace.
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Labels
Area: MIR optimizationsCategory: This is a bug.Issue: A query cycle occurred while none was expectedMedium priorityStatus: A bisection has been found for this issueStatus: A Minimal Complete and Verifiable Example has been found for this issueRelevant to the compiler team, which will review and decide on the PR/issue.Performance or correctness regression from one stable version to another.