rustc output no longer reproducible if it crashes #145424
Description
I tried this code:
pub fn main() { break rust }command:
RUST_BACKTRACE=0 RUSTC_ICE=0 rustc a.rs
I expected to see this happen:
Equal output on all runs (current behavior on stable 1.89.0 )
Instead, this happened:
thread id that changes every run
--- 1 2025-08-15 08:31:33.671734318 +0200 +++ 2 2025-08-15 08:31:34.932738329 +0200 @@ -21,7 +21,7 @@ = note: rustc 1.91.0-nightly (898aff704 2025-08-14) running on x86_64-unknown-linux-gnu -thread 'rustc' (3427246) panicked at compiler/rustc_hir_typeck/src/lib.rs:549:10: +thread 'rustc' (3427309) panicked at compiler/rustc_hir_typeck/src/lib.rs:549:10: Box<dyn Any> note: run with `RUST_BACKTRACE=1` environment variable to display a backtraceMeta
since #115746
rustc --version --verbose:
rustc 1.91.0-nightly (898aff704 2025-08-14) binary: rustc commit-hash: 898aff704d6f0d00343f21d31b8b9bfac8e43007 commit-date: 2025-08-14 host: x86_64-unknown-linux-gnu release: 1.91.0-nightly LLVM version: 21.1.0