rust-lang / rust-lang/rust

[ICE]: corecursive trait solver failure with lifetimes

Open
#162,343 6 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

A-trait-system C-bug I-ICE S-has-bisection S-has-mcve T-compiler WG-trait-system-refactor
Dominant language
Rust
Stars
119k
Forks
16.1k
PR metrics pending

Description

Code

code here, branch here

Meta

rustc --version --verbose:

rustc 1.100.0-nightly (0ed41eb41 2026-09-04)
binary: rustc
commit-hash: 0ed41eb4142dda2df61eb1145a312c1a9d62eb56
commit-date: 2026-09-04
host: x86_64-unknown-linux-gnu
release: 1.100.0-nightly
LLVM version: 23.1.1

rustc 1.98.1 (48a229cea 2026-09-01)
binary: rustc
commit-hash: 48a229ceaefd4985c50990b14116b6d856af0985
commit-date: 2026-09-01
host: x86_64-unknown-linux-gnu
release: 1.98.1
LLVM version: 22.1.8
Error output

On nightly:

error: internal compiler error: /rustc-dev/0ed41eb4142dda2df61eb1145a312c1a9d62eb56/compiler/rustc_middle/src/ty/instance.rs:640:21: failed to resolve instance for <ListValue<'_> as RawMessage>::clear
   --> test-ice/src/lib.rs:250:9
    |
250 |         <ListValue<'a> as ::bilrost::encoding::RawMessage>::clear(val);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[...]

query stack during panic:
#0 [items_of_instance] collecting items used by `<impl at test-ice/src/lib.rs:241:1: 244:84>::clear`
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items

On stable: No error (‼️), consumes resources seemingly indefinitely without terminating

Backtrace 

thread 'rustc' (2849301) panicked at /rustc-dev/0ed41eb4142dda2df61eb1145a312c1a9d62eb56/compiler/rustc_middle/src/ty/instance.rs:640:21:
Box<dyn Any>
stack backtrace:
   0:     0x79f5ec291516 - <<std[d4c1480f659289a4]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[645f4c3e01480c61]::fmt::Display>::fmt
   1:     0x79f5eca0ba8f - core[645f4c3e01480c61]::fmt::write
   2:     0x79f5ec2a660c - <std[d4c1480f659289a4]::sys::stdio::unix::Stderr as core[645f4c3e01480c61]::io::write::Write>::write_fmt
   3:     0x79f5ec263dba - std[d4c1480f659289a4]::panicking::default_hook::{closure#0}
   4:     0x79f5ec285813 - std[d4c1480f659289a4]::panicking::default_hook
   5:     0x79f5eb1dcaef - std[d4c1480f659289a4]::panicking::update_hook::<alloc[85239869be382ab2]::boxed::Box<rustc_driver_impl[52b061d793d3365c]::install_ice_hook::{closure#1}>>::{closure#0}
   6:     0x79f5ec285cb2 - std[d4c1480f659289a4]::panicking::panic_with_hook
   7:     0x79f5eb20b7d4 - std[d4c1480f659289a4]::panicking::begin_panic::<rustc_errors[a73332a6523420a1]::ExplicitBug>::{closure#0}
   8:     0x79f5eb204566 - std[d4c1480f659289a4]::sys::backtrace::__rust_end_short_backtrace::<std[d4c1480f659289a4]::panicking::begin_panic<rustc_errors[a73332a6523420a1]::ExplicitBug>::{closure#0}, !>
   9:     0x79f5eb20429b - std[d4c1480f659289a4]::panicking::begin_panic::<rustc_errors[a73332a6523420a1]::ExplicitBug>
  10:     0x79f5eb217031 - <rustc_errors[a73332a6523420a1]::diagnostic::BugAbort as rustc_errors[a73332a6523420a1]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  11:     0x79f5eb7894ac - <rustc_errors[a73332a6523420a1]::DiagCtxtHandle>::span_bug::<rustc_span[fb518c986e8dde63]::span_encoding::Span, alloc[85239869be382ab2]::string::String>
  12:     0x79f5eb7b7cc6 - rustc_middle[7aa4fce01e3768ef]::util::bug::opt_span_bug_fmt::<rustc_span[fb518c986e8dde63]::span_encoding::Span>::{closure#0}
  13:     0x79f5eb7b80e2 - rustc_middle[7aa4fce01e3768ef]::ty::context::tls::with_opt::<rustc_middle[7aa4fce01e3768ef]::util::bug::opt_span_bug_fmt<rustc_span[fb518c986e8dde63]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  14:     0x79f5eb7a3400 - rustc_middle[7aa4fce01e3768ef]::ty::context::tls::with_context_opt::<rustc_middle[7aa4fce01e3768ef]::ty::context::tls::with_opt<rustc_middle[7aa4fce01e3768ef]::util::bug::opt_span_bug_fmt<rustc_span[fb518c986e8dde63]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  15:     0x79f5e954aa38 - rustc_middle[7aa4fce01e3768ef]::util::bug::span_bug_fmt::<rustc_span[fb518c986e8dde63]::span_encoding::Span>
  16:     0x79f5ece36103 - <rustc_middle[7aa4fce01e3768ef]::ty::instance::Instance>::expect_resolve
  17:     0x79f5ece38e92 - rustc_monomorphize[f697b03780a3381a]::collector::items_of_instance
  18:     0x79f5ece37c91 - rustc_query_impl[52f5aaaf2d2e4217]::query_vtables::items_of_instance::invoke_provider_fn::__rust_begin_short_backtrace
  19:     0x79f5ed982e81 - rustc_query_impl[52f5aaaf2d2e4217]::execution::try_execute_query::<rustc_middle[7aa4fce01e3768ef]::query::caches::DefaultCache<(rustc_middle[7aa4fce01e3768ef]::ty::instance::Instance, rustc_middle[7aa4fce01e3768ef]::mono::CollectionMode), rustc_middle[7aa4fce01e3768ef]::query::erase::ErasedData<[u8; 32usize]>>, true>
  20:     0x79f5ed9824ab - rustc_query_impl[52f5aaaf2d2e4217]::query_vtables::items_of_instance::execute_query_incr::__rust_end_short_backtrace
  21:     0x79f5edb5f22e - rustc_monomorphize[f697b03780a3381a]::collector::collect_items_rec
  22:     0x79f5edb658b4 - rustc_monomorphize[f697b03780a3381a]::collector::collect_crate_mono_items::{closure#1}::{closure#0}
  23:     0x79f5edb661e3 - rustc_monomorphize[f697b03780a3381a]::partitioning::collect_and_partition_mono_items
  24:     0x79f5edc5cf16 - rustc_query_impl[52f5aaaf2d2e4217]::query_vtables::collect_and_partition_mono_items::invoke_provider_fn::__rust_begin_short_backtrace
  25:     0x79f5ee305451 - rustc_query_impl[52f5aaaf2d2e4217]::execution::try_execute_query::<rustc_middle[7aa4fce01e3768ef]::query::caches::SingleCache<rustc_middle[7aa4fce01e3768ef]::query::erase::ErasedData<[u8; 24usize]>>, true>
  26:     0x79f5ee304e8c - rustc_query_impl[52f5aaaf2d2e4217]::query_vtables::collect_and_partition_mono_items::execute_query_incr::__rust_end_short_backtrace
  27:     0x79f5ed59be03 - rustc_codegen_ssa[ce71d2ce136ae586]::back::symbol_export::exported_generic_symbols_provider_local
  28:     0x79f5edb4fa74 - rustc_query_impl[52f5aaaf2d2e4217]::query_vtables::exported_generic_symbols::invoke_provider_fn::__rust_begin_short_backtrace
  29:     0x79f5edb4e594 - rustc_query_impl[52f5aaaf2d2e4217]::execution::try_execute_query::<rustc_data_structures[35e205c67e017b95]::vec_cache::VecCache<rustc_span[fb518c986e8dde63]::def_id::CrateNum, rustc_middle[7aa4fce01e3768ef]::query::erase::ErasedData<[u8; 16usize]>, rustc_middle[7aa4fce01e3768ef]::dep_graph::graph::DepNodeIndex>, true>
  30:     0x79f5edb4dd27 - rustc_query_impl[52f5aaaf2d2e4217]::query_vtables::exported_generic_symbols::execute_query_incr::__rust_end_short_backtrace
  31:     0x79f5edc0ad97 - <rustc_metadata[8b637ccb72f2b57d]::rmeta::encoder::EncodeContext>::encode_crate_root
  32:     0x79f5edbedee1 - rustc_metadata[8b637ccb72f2b57d]::rmeta::encoder::encode_metadata::{closure#3}
  33:     0x79f5edbec504 - rustc_metadata[8b637ccb72f2b57d]::rmeta::encoder::encode_metadata
  34:     0x79f5edea7190 - rustc_metadata[8b637ccb72f2b57d]::fs::encode_and_write_metadata
  35:     0x79f5ede0363e - <rustc_interface[facc905b6ccf4600]::queries::Linker>::codegen_and_build_linker
  36:     0x79f5eddfae41 - rustc_interface[facc905b6ccf4600]::interface::run_compiler::<(), rustc_driver_impl[52b061d793d3365c]::run_compiler::{closure#0}>::{closure#2}
  37:     0x79f5ede89602 - std[d4c1480f659289a4]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[facc905b6ccf4600]::util::run_in_thread_with_globals<rustc_interface[facc905b6ccf4600]::util::run_in_thread_pool_with_globals<rustc_interface[facc905b6ccf4600]::interface::run_compiler<(), rustc_driver_impl[52b061d793d3365c]::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  38:     0x79f5ede893ad - <std[d4c1480f659289a4]::thread::lifecycle::spawn_unchecked<rustc_interface[facc905b6ccf4600]::util::run_in_thread_with_globals<rustc_interface[facc905b6ccf4600]::util::run_in_thread_pool_with_globals<rustc_interface[facc905b6ccf4600]::interface::run_compiler<(), rustc_driver_impl[52b061d793d3365c]::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[645f4c3e01480c61]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  39:     0x79f5ede86f47 - <std[d4c1480f659289a4]::sys::thread::unix::Thread>::new::thread_start
  40:     0x79f5e6ea407a - <unknown>
  41:     0x79f5e6f3772c - <unknown>
  42:                0x0 - <unknown>

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the reproducer in test-ice/src/lib.rs on the rust-ice-2-bilrost branch, then build it with the reported nightly and stable Rust versions. Compare the nightly ICE and stable non-terminating resource use around the RawMessage::clear implementation at lines 241–250. Done means the reproducer no longer triggers an internal compiler error or indefinite resource consumption.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
30/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.