rust-lang / rust-lang/rust

ICE `error performing operation: fully_perform`

Open
#140,123 15 comments 0 reactions 1 assignee View on GitHub

@dingxiangfei2009 is already working on this.

Since Sep 2, 2025.

A-array A-const-eval C-bug I-ICE S-bug-has-test S-has-mcve T-compiler
Dominant language
Rust
Stars
119k
Forks
16.1k
PR metrics pending

Description

ICE when const {} initializing mutable references in [expr; N] array initializers where N is >= 2. Does not happen when setting every element explicitly [expr, expr]. Interestingly you cannot use const { &mut[] } directly and must use a function call to get around it. I will make another issue for that.

Related issue: "Compile error when using &mut in explicity const context directly" #140126

Code
// error[E0764]: mutable references are not allowed in the final value of constants
// pub const NO_COMPILE: [&mut [f32]; 2] = [const { &mut[] }; 2];
const OK: [&mut [()]; 2] = [empty_mut(), empty_mut()];
const ICE: [&mut [()]; 2] = [const { empty_mut() }; 2];

// Any kind of fn call gets around E0764.
const fn empty_mut() -> &'static mut [()] {
    &mut []
}
Meta

Occurs in version >= 1.83.0. Older versions fail to compile normally due to mutable references in const.

rustc --version --verbose:

rustc 1.88.0-nightly (b8c54d635 2025-04-20)
binary: rustc
commit-hash: b8c54d6358926028ac2fab1ec2b8665c70edb1c0
commit-date: 2025-04-20
host: x86_64-unknown-linux-gnu
release: 1.88.0-nightly
LLVM version: 20.1.2
Error output
   Compiling rust_playground2 v0.1.0 (/tmp/rust_playground2)
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: error performing operation: fully_perform
 --> src/lib.rs:1:34
  |
1 | pub const ICE: [&mut [f32]; 2] = [const { empty_mut() }; 2];
  |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
note: delayed at /rustc/b8c54d6358926028ac2fab1ec2b8665c70edb1c0/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:87:25 - disabled backtrace
 --> src/lib.rs:1:34
  |
1 | pub const ICE: [&mut [f32]; 2] = [const { empty_mut() }; 2];
  |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^

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 `/tmp/rust_playground2/rustc-ice-2025-04-21T16_27_11-21059.txt` to your bug report

note: compiler flags: --crate-type lib -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED]

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

query stack during panic:
end of query stack
error: could not compile `rust_playground2` (lib)

Caused by:
  process didn't exit successfully: `/home/redram/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc --crate-name rust_playground2 --edition=2024 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values())' -C metadata=1f5395c8c0077482 -C extra-filename=-be321adee2c2c0a3 --out-dir /mnt/extra/cargo_target/debug/deps -C incremental=/mnt/extra/cargo_target/debug/incremental -L dependency=/mnt/extra/cargo_target/debug/deps` (exit status: 101)
Backtrace 

delayed bug: error performing operation: fully_perform
   0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
   1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
   2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
   4: <rustc_borrowck::type_check::TypeChecker>::prove_trait_ref
   5: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_rvalue
   6: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_body
   7: rustc_borrowck::do_mir_borrowck
   8: rustc_borrowck::mir_borrowck
   9: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
  10: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
  11: rustc_query_impl::query_impl::mir_borrowck::get_query_incr::__rust_end_short_backtrace
  12: rustc_mir_transform::mir_drops_elaborated_and_const_checked
  13: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_drops_elaborated_and_const_checked::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
  14: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
  15: rustc_query_impl::query_impl::mir_drops_elaborated_and_const_checked::get_query_incr::__rust_end_short_backtrace
  16: rustc_mir_transform::mir_for_ctfe
  17: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_for_ctfe::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
  18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
  19: rustc_query_impl::query_impl::mir_for_ctfe::get_query_incr::__rust_end_short_backtrace
  20: <rustc_const_eval::interpret::eval_context::InterpCx<rustc_const_eval::const_eval::machine::CompileTimeMachine>>::load_mir
  21: rustc_const_eval::const_eval::eval_queries::eval_to_allocation_raw_provider
  22: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>>
  23: <rustc_query_impl::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>)>>::call_once
  24: <rustc_query_system::query::plumbing::execute_job_incr<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt>::{closure#2}::{closure#2} as core::ops::function::FnOnce<((rustc_query_impl::plumbing::QueryCtxt, rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>), rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>)>>::call_once
  25: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
  26: rustc_query_impl::query_impl::eval_to_allocation_raw::get_query_incr::__rust_end_short_backtrace
  27: rustc_const_eval::const_eval::eval_queries::eval_to_const_value_raw_provider
  28: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::eval_to_const_value_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>>
  29: <rustc_query_impl::query_impl::eval_to_const_value_raw::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>)>>::call_once
  30: <rustc_query_system::query::plumbing::execute_job_incr<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt>::{closure#2}::{closure#2} as core::ops::function::FnOnce<((rustc_query_impl::plumbing::QueryCtxt, rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>), rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>)>>::call_once
  31: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::PseudoCanonicalInput<rustc_middle::mir::interpret::GlobalId>, rustc_middle::query::erase::Erased<[u8; 24]>>, false, true, false>, rustc_query_impl::plumbing::QueryCtxt, true>
  32: rustc_query_impl::query_impl::eval_to_const_value_raw::get_query_incr::__rust_end_short_backtrace
  33: rustc_hir_analysis::check_crate
  34: rustc_interface::passes::run_required_analyses
  35: rustc_interface::passes::analysis
  36: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
  37: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
  38: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
  39: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  40: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
  41: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  42: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  43: std::sys::pal::unix::thread::Thread::new::thread_start
  44: <unknown>
  45: <unknown>



rustc version: 1.88.0-nightly (b8c54d635 2025-04-20)
platform: x86_64-unknown-linux-gnu

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.

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.