Error: A dep graph node (mir_drops_elaborated_and_const_checked) does not have an unique index.

[rmvermeulen]

I'm reporting this just in case these traces tell something useful, but:

• I cannot reproduce this after rustup update toolchain nightly
• I cannot reinstall the toolchain that produced it afaik since rustup install toolchain nightly-2025-06-40 installs nightly-2025-06-30-x86_64-unknown-linux-gnu - rustc 1.90.0-nightly (35f603652 2025-06-29) (note the different sha) and this version does not reproduce it.
• I haven't ever built the rust compiler and cannot dive in right now, but the exact code I was running this on has been committed, and if required I should be able to run the same command on it with the exact compiler build within a few days.

Cheers!

rustup update output

nightly-x86_64-unknown-linux-gnu updated - rustc 1.90.0-nightly (71e4c005c 2025-07-01) (from rustc 1.90.0-nightly (f26e58023 2025-06-30))

Error output

--- dev/bed ‹main*➔ AM› » cargo r Cargo.toml --timeout 1
   Compiling bed v0.1.0 (/mnt/data/Projects/bed)

thread 'rustc' panicked at /rustc-dev/f26e58023071e71636a3c72ac3a2bf89b1f76706/compiler/rustc_query_system/src/dep_graph/serialized.rs:284:21:
Error: A dep graph node (mir_drops_elaborated_and_const_checked) does not have an unique index. Running a clean build on a nightly compiler with `-Z incremental-verify-ich` can help narrow down the issue for reporting. A clean build may also work around the issue.

                     DepNode: DepKind { variant: 56 }(d0da2204872fcb9e-c5673b7a7c4076d)
stack backtrace:
   0:     0x76e72432e243 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h5d4004938ff2c5de
   1:     0x76e724a0277f - core::fmt::write::he40d39caeedce22d
   2:     0x76e724323e83 - std::io::Write::write_fmt::h6b481595dd1fc53f
   3:     0x76e72432e0a2 - std::sys::backtrace::BacktraceLock::print::h6122e56851fd7e04
   4:     0x76e724331b9a - std::panicking::default_hook::{{closure}}::h5da9a6ee005a6c0c
   5:     0x76e72433171f - std::panicking::default_hook::he77158b4319b132a
   6:     0x76e7234095d3 - std[abb3b870cf4d8027]::panicking::update_hook::<alloc[3b9c56f51ca07bea]::boxed::Box<rustc_driver_impl[7eb6cf164257341f]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x76e7243323eb - std::panicking::rust_panic_with_hook::hbc48a4f07e431d11
   8:     0x76e7243320ea - std::panicking::begin_panic_handler::{{closure}}::hc7687229f89659e1
   9:     0x76e72432e719 - std::sys::backtrace::__rust_end_short_backtrace::he778acc2814e945f
  10:     0x76e724331dcd - __rustc[23c8550fe4817b53]::rust_begin_unwind
  11:     0x76e720aa6430 - core::panicking::panic_fmt::h83f0c88dbe3c1f31
  12:     0x76e725df2a33 - rustc_incremental[d87d765a6239e68e]::persist::load::setup_dep_graph
  13:     0x76e725c66192 - rustc_interface[f681bac94ac292a9]::interface::run_compiler::<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}
  14:     0x76e72341be94 - <rustc_thread_pool[7c862dc4ae444296]::job::StackJob<rustc_thread_pool[7c862dc4ae444296]::latch::LatchRef<rustc_thread_pool[7c862dc4ae444296]::latch::LockLatch>, <rustc_thread_pool[7c862dc4ae444296]::registry::Registry>::in_worker_cold<<rustc_thread_pool[7c862dc4ae444296]::thread_pool::ThreadPool>::install<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}::{closure#0}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()> as rustc_thread_pool[7c862dc4ae444296]::job::Job>::execute
  15:     0x76e72405529e - <rustc_thread_pool[7c862dc4ae444296]::registry::WorkerThread>::wait_until_cold
  16:     0x76e724052cb1 - <rustc_thread_pool[7c862dc4ae444296]::registry::ThreadBuilder>::run
  17:     0x76e72340211d - std[abb3b870cf4d8027]::sys::backtrace::__rust_begin_short_backtrace::<<rustc_thread_pool[7c862dc4ae444296]::ThreadPoolBuilder>::build_scoped<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
  18:     0x76e72340e7e2 - <<std[abb3b870cf4d8027]::thread::Builder>::spawn_unchecked_<<rustc_thread_pool[7c862dc4ae444296]::ThreadPoolBuilder>::build_scoped<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>::{closure#1} as core[7243450d3d38063e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  19:     0x76e725c0ddfd - std::sys::pal::unix::thread::Thread::new::thread_start::h277742a54d34f956
  20:     0x76e71f6a57eb - <unknown>
  21:     0x76e71f72918c - <unknown>
  22:                0x0 - <unknown>

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: please make sure that you have updated to the latest nightly

note: please attach the file at `/mnt/data/Projects/bed/rustc-ice-2025-07-02T20_01_36-697837.txt` to your bug report

note: compiler flags: --crate-type lib -C opt-level=1 -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on -C linker=clang -C incremental=[REDACTED] -C link-arg=-fuse-ld=/usr/bin/mold -Z share-generics=y -Z threads=0

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack
error: could not compile `bed` (lib)

Backtrace

thread 'rustc' panicked at /rustc-dev/f26e58023071e71636a3c72ac3a2bf89b1f76706/compiler/rustc_query_system/src/dep_graph/serialized.rs:284:21: Error: A dep graph node (mir_drops_elaborated_and_const_checked) does not have an unique index. Running a clean build on a nightly compiler with `-Z incremental-verify-ich` can help narrow down the issue for reporting. A clean build may also work around the issue.

                     DepNode: DepKind { variant: 56 }(d0da2204872fcb9e-c5673b7a7c4076d)
stack backtrace:
   0:     0x76e7243183b5 - std::backtrace::Backtrace::create::h96aa47e8f3e9d114
   1:     0x76e724318305 - std::backtrace::Backtrace::force_capture::hd3a7d8938d13aa88
   2:     0x76e72340a60c - std[abb3b870cf4d8027]::panicking::update_hook::<alloc[3b9c56f51ca07bea]::boxed::Box<rustc_driver_impl[7eb6cf164257341f]::install_ice_hook::{closure#1}>>::{closure#0}
   3:     0x76e7243323eb - std::panicking::rust_panic_with_hook::hbc48a4f07e431d11
   4:     0x76e7243320ea - std::panicking::begin_panic_handler::{{closure}}::hc7687229f89659e1
   5:     0x76e72432e719 - std::sys::backtrace::__rust_end_short_backtrace::he778acc2814e945f
   6:     0x76e724331dcd - __rustc[23c8550fe4817b53]::rust_begin_unwind
   7:     0x76e720aa6430 - core::panicking::panic_fmt::h83f0c88dbe3c1f31
   8:     0x76e725df2a33 - rustc_incremental[d87d765a6239e68e]::persist::load::setup_dep_graph
   9:     0x76e725c66192 - rustc_interface[f681bac94ac292a9]::interface::run_compiler::<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}
  10:     0x76e72341be94 - <rustc_thread_pool[7c862dc4ae444296]::job::StackJob<rustc_thread_pool[7c862dc4ae444296]::latch::LatchRef<rustc_thread_pool[7c862dc4ae444296]::latch::LockLatch>, <rustc_thread_pool[7c862dc4ae444296]::registry::Registry>::in_worker_cold<<rustc_thread_pool[7c862dc4ae444296]::thread_pool::ThreadPool>::install<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}::{closure#0}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()> as rustc_thread_pool[7c862dc4ae444296]::job::Job>::execute
  11:     0x76e72405529e - <rustc_thread_pool[7c862dc4ae444296]::registry::WorkerThread>::wait_until_cold
  12:     0x76e724052cb1 - <rustc_thread_pool[7c862dc4ae444296]::registry::ThreadBuilder>::run
  13:     0x76e72340211d - std[abb3b870cf4d8027]::sys::backtrace::__rust_begin_short_backtrace::<<rustc_thread_pool[7c862dc4ae444296]::ThreadPoolBuilder>::build_scoped<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
  14:     0x76e72340e7e2 - <<std[abb3b870cf4d8027]::thread::Builder>::spawn_unchecked_<<rustc_thread_pool[7c862dc4ae444296]::ThreadPoolBuilder>::build_scoped<rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface[f681bac94ac292a9]::util::run_in_thread_pool_with_globals<rustc_interface[f681bac94ac292a9]::interface::run_compiler<(), rustc_driver_impl[7eb6cf164257341f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>::{closure#1} as core[7243450d3d38063e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  15:     0x76e725c0ddfd - std::sys::pal::unix::thread::Thread::new::thread_start::h277742a54d34f956
  16:     0x76e71f6a57eb - <unknown>
  17:     0x76e71f72918c - <unknown>
  18:                0x0 - <unknown>


rustc version: 1.90.0-nightly (f26e58023 2025-06-30)
platform: x86_64-unknown-linux-gnu

[cjgillot]

@Zoxc do you have any idea what could cause this?

[matthiaskrgr]

oh is this like a weird combination of parallel compiler + incr comp? :|

[cyrgani]

this is probably the same as #141540

[rmvermeulen]

I'm not at my machine now, and I didn't think of mentioning this somehow, but this was in a bevy project based on the minimal template.

https://github.com/TheBevyFlock/bevy_new_minimal/

It has a lot of flags set both in cargo.toml and .cargo/config.toml. I enabled everything for Linux + mold and bevy/dynamic_linking.

[rmvermeulen]

If I run cargo test on a sequence of commits (~10) this will pretty reliably happen; the tests start failing to build and I get some ice files for each. If I rm -rf target/debug/incremental && cargo test it finishes succesfully. I'll try to get a minimal working example out of this.