ICE: Result::unwrap() on an Err value: InterpErrorInfo(InterpErrorInfoInner { kind: UndefinedBehavior(BoundsCheckFailed .. #151079
Description
auto-reduced (treereduce-rust):
//@compile-flags: -Zmir-opt-level=5 -Clink-dead-code=true
#![feature(min_generic_const_args)]
#![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
use std::marker::ConstParamTy_;
fn foo<T: ConstParamTy_, const N: usize, const M: [T; N]>() -> [T; N] {
M
}
fn main() {
let a: [u8; 2] = foo::<u8, 2, { [0, 0, 0] }>();
}original:
//@ check-pass
#![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
#![allow(incomplete_features)]
use std::marker::ConstParamTy_;
fn foo<T: ConstParamTy_, const N: usize, const M: [T; N]>() -> [T; N] {
M
}
fn main() {
let a: [u8; 2] = foo::<u8, 2, { [0,0,0] }>();
}Version information
rustc 1.94.0-nightly (9b8162963 2026-01-13)
binary: rustc
commit-hash: 9b81629631b382fd49ee3a20ac47797b1467e52d
commit-date: 2026-01-13
host: x86_64-unknown-linux-gnu
release: 1.94.0-nightly
LLVM version: 21.1.8
Possibly related line of code:
rust/compiler/rustc_const_eval/src/const_eval/valtrees.rs
Lines 421 to 433 in 9b81629
Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zmir-opt-level=5 -Clink-dead-code=true -Zcrate-attr=feature(min_generic_const_args)
Program output
warning: the feature `unsized_const_params` is incomplete and may not be safe to use and/or cause compiler crashes
--> /tmp/icemaker_global_tempdir.wjemz51V43gv/rustc_testrunner_tmpdir_reporting.8FXotATA72YN/mvce.rs:1:30
|
1 | #![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
| ^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #95174 <https://github.com/rust-lang/rust/issues/95174> for more information
= note: `#[warn(incomplete_features)]` on by default
warning: the feature `generic_const_parameter_types` is incomplete and may not be safe to use and/or cause compiler crashes
--> /tmp/icemaker_global_tempdir.wjemz51V43gv/rustc_testrunner_tmpdir_reporting.8FXotATA72YN/mvce.rs:1:52
|
1 | #![feature(adt_const_params, unsized_const_params, generic_const_parameter_types)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #137626 <https://github.com/rust-lang/rust/issues/137626> for more information
warning: the feature `min_generic_const_args` is incomplete and may not be safe to use and/or cause compiler crashes
--> <crate attribute>:1:12
|
1 | #![feature(min_generic_const_args)]
| ^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #132980 <https://github.com/rust-lang/rust/issues/132980> for more information
warning: unused variable: `a`
--> /tmp/icemaker_global_tempdir.wjemz51V43gv/rustc_testrunner_tmpdir_reporting.8FXotATA72YN/mvce.rs:10:9
|
10 | let a: [u8; 2] = foo::<u8, 2, { [0, 0, 0] }>();
| ^ help: if this is intentional, prefix it with an underscore: `_a`
|
= note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
thread 'rustc' (1941695) panicked at /rustc-dev/9b81629631b382fd49ee3a20ac47797b1467e52d/compiler/rustc_const_eval/src/const_eval/valtrees.rs:427:60:
called `Result::unwrap()` on an `Err` value: InterpErrorInfo(InterpErrorInfoInner { kind: UndefinedBehavior(BoundsCheckFailed { len: 2, index: 2 }), backtrace: InterpErrorBacktrace { backtrace: None } })
stack backtrace:
0: 0x7fb14a635093 - <<std[2ade4c2364de62da]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[70014f3701156057]::fmt::Display>::fmt
1: 0x7fb14ac0fb48 - core[70014f3701156057]::fmt::write
2: 0x7fb14a64ba86 - <std[2ade4c2364de62da]::sys::stdio::unix::Stderr as std[2ade4c2364de62da]::io::Write>::write_fmt
3: 0x7fb14a60b108 - std[2ade4c2364de62da]::panicking::default_hook::{closure#0}
4: 0x7fb14a6287c3 - std[2ade4c2364de62da]::panicking::default_hook
5: 0x7fb14960c68a - std[2ade4c2364de62da]::panicking::update_hook::<alloc[bf1f08ca38e38ea3]::boxed::Box<rustc_driver_impl[48bdb3468b385e51]::install_ice_hook::{closure#1}>>::{closure#0}
6: 0x7fb14a628aa2 - std[2ade4c2364de62da]::panicking::panic_with_hook
7: 0x7fb14a60b1c8 - std[2ade4c2364de62da]::panicking::panic_handler::{closure#0}
8: 0x7fb14a5ff679 - std[2ade4c2364de62da]::sys::backtrace::__rust_end_short_backtrace::<std[2ade4c2364de62da]::panicking::panic_handler::{closure#0}, !>
9: 0x7fb14a60cc9d - __rustc[2d9923b8307f5353]::rust_begin_unwind
10: 0x7fb14718318c - core[70014f3701156057]::panicking::panic_fmt
11: 0x7fb146ef4ef2 - core[70014f3701156057]::result::unwrap_failed
12: 0x7fb14b0ba94e - rustc_const_eval[7181a74e73bdfbc4]::const_eval::valtrees::valtree_into_mplace
13: 0x7fb14bcefddc - rustc_const_eval[7181a74e73bdfbc4]::const_eval::valtrees::valtree_to_const_value
14: 0x7fb14bcef7ab - <rustc_const_eval[7181a74e73bdfbc4]::provide::{closure#1} as core[70014f3701156057]::ops::function::FnOnce<(rustc_middle[a808b96dc0c8b39]::ty::context::TyCtxt, rustc_middle[a808b96dc0c8b39]::ty::consts::valtree::Value)>>::call_once
15: 0x7fb14bcef756 - rustc_query_impl[d3207ad19da6bae6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[d3207ad19da6bae6]::query_impl::valtree_to_const_val::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 24usize]>>
16: 0x7fb14bcef71f - <rustc_query_impl[d3207ad19da6bae6]::query_impl::valtree_to_const_val::dynamic_query::{closure#2} as core[70014f3701156057]::ops::function::FnOnce<(rustc_middle[a808b96dc0c8b39]::ty::context::TyCtxt, rustc_middle[a808b96dc0c8b39]::ty::consts::valtree::Value)>>::call_once
17: 0x7fb14bceed4c - rustc_query_system[ac97840b0086b723]::query::plumbing::try_execute_query::<rustc_query_impl[d3207ad19da6bae6]::DynamicConfig<rustc_query_system[ac97840b0086b723]::query::caches::DefaultCache<rustc_middle[a808b96dc0c8b39]::ty::consts::valtree::Value, rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[d3207ad19da6bae6]::plumbing::QueryCtxt, false>
18: 0x7fb14bceea65 - rustc_query_impl[d3207ad19da6bae6]::query_impl::valtree_to_const_val::get_query_non_incr::__rust_end_short_backtrace
19: 0x7fb14b9b5e0f - <rustc_const_eval[7181a74e73bdfbc4]::interpret::eval_context::InterpCx<rustc_const_eval[7181a74e73bdfbc4]::const_eval::dummy_machine::DummyMachine>>::eval_mir_constant
20: 0x7fb14b9b6e3e - <rustc_mir_transform[60a44e365f7ed4e9]::gvn::VnState>::eval_to_const
21: 0x7fb14b9c62d2 - <rustc_mir_transform[60a44e365f7ed4e9]::gvn::VnState as rustc_middle[a808b96dc0c8b39]::mir::visit::MutVisitor>::visit_assign
22: 0x7fb14b9c5316 - <rustc_mir_transform[60a44e365f7ed4e9]::gvn::GVN as rustc_mir_transform[60a44e365f7ed4e9]::pass_manager::MirPass>::run_pass
23: 0x7fb14ac0739d - rustc_mir_transform[60a44e365f7ed4e9]::run_optimization_passes
24: 0x7fb14b416d4f - rustc_mir_transform[60a44e365f7ed4e9]::optimized_mir
25: 0x7fb14b41696f - rustc_query_impl[d3207ad19da6bae6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[d3207ad19da6bae6]::query_impl::optimized_mir::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 8usize]>>
26: 0x7fb14ac18386 - rustc_query_system[ac97840b0086b723]::query::plumbing::try_execute_query::<rustc_query_impl[d3207ad19da6bae6]::DynamicConfig<rustc_query_system[ac97840b0086b723]::query::caches::DefIdCache<rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[d3207ad19da6bae6]::plumbing::QueryCtxt, false>
27: 0x7fb14ac1795b - rustc_query_impl[d3207ad19da6bae6]::query_impl::optimized_mir::get_query_non_incr::__rust_end_short_backtrace
28: 0x7fb1473cada1 - <rustc_middle[a808b96dc0c8b39]::ty::context::TyCtxt>::instance_mir
29: 0x7fb14b67ac1f - rustc_monomorphize[a4e61b93c8fa6a66]::collector::items_of_instance
30: 0x7fb14b67abbc - rustc_query_impl[d3207ad19da6bae6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[d3207ad19da6bae6]::query_impl::items_of_instance::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 32usize]>>
31: 0x7fb14b8d7894 - rustc_query_system[ac97840b0086b723]::query::plumbing::try_execute_query::<rustc_query_impl[d3207ad19da6bae6]::DynamicConfig<rustc_query_system[ac97840b0086b723]::query::caches::DefaultCache<(rustc_middle[a808b96dc0c8b39]::ty::instance::Instance, rustc_middle[a808b96dc0c8b39]::mir::mono::CollectionMode), rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 32usize]>>, false, false, false>, rustc_query_impl[d3207ad19da6bae6]::plumbing::QueryCtxt, false>
32: 0x7fb14b8d74b3 - rustc_query_impl[d3207ad19da6bae6]::query_impl::items_of_instance::get_query_non_incr::__rust_end_short_backtrace
33: 0x7fb14c0e5c58 - rustc_monomorphize[a4e61b93c8fa6a66]::collector::collect_items_rec
34: 0x7fb14af47eab - rustc_monomorphize[a4e61b93c8fa6a66]::collector::collect_crate_mono_items::{closure#1}::{closure#0}
35: 0x7fb14b2d8836 - rustc_monomorphize[a4e61b93c8fa6a66]::partitioning::collect_and_partition_mono_items
36: 0x7fb14c0038a4 - rustc_query_impl[d3207ad19da6bae6]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[d3207ad19da6bae6]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 24usize]>>
37: 0x7fb14c003889 - <rustc_query_impl[d3207ad19da6bae6]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core[70014f3701156057]::ops::function::FnOnce<(rustc_middle[a808b96dc0c8b39]::ty::context::TyCtxt, ())>>::call_once
38: 0x7fb14c0033de - rustc_query_system[ac97840b0086b723]::query::plumbing::try_execute_query::<rustc_query_impl[d3207ad19da6bae6]::DynamicConfig<rustc_query_system[ac97840b0086b723]::query::caches::SingleCache<rustc_middle[a808b96dc0c8b39]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[d3207ad19da6bae6]::plumbing::QueryCtxt, false>
39: 0x7fb14c003183 - rustc_query_impl[d3207ad19da6bae6]::query_impl::collect_and_partition_mono_items::get_query_non_incr::__rust_end_short_backtrace
40: 0x7fb14c00a508 - rustc_codegen_ssa[3d3f98e3151f9062]::base::codegen_crate::<rustc_codegen_llvm[5765bde0af8a4c1a]::LlvmCodegenBackend>
41: 0x7fb14c007fc3 - <rustc_codegen_llvm[5765bde0af8a4c1a]::LlvmCodegenBackend as rustc_codegen_ssa[3d3f98e3151f9062]::traits::backend::CodegenBackend>::codegen_crate
42: 0x7fb14bfb748c - <rustc_interface[372b2d608f466254]::queries::Linker>::codegen_and_build_linker
43: 0x7fb14bfb4a9c - <rustc_interface[372b2d608f466254]::passes::create_and_enter_global_ctxt<core[70014f3701156057]::option::Option<rustc_interface[372b2d608f466254]::queries::Linker>, rustc_driver_impl[48bdb3468b385e51]::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core[70014f3701156057]::ops::function::FnOnce<(&rustc_session[4ad34451d848125f]::session::Session, rustc_middle[a808b96dc0c8b39]::ty::context::CurrentGcx, alloc[bf1f08ca38e38ea3]::sync::Arc<rustc_data_structures[de9cc80261963238]::jobserver::Proxy>, &std[2ade4c2364de62da]::sync::once_lock::OnceLock<rustc_middle[a808b96dc0c8b39]::ty::context::GlobalCtxt>, &rustc_data_structures[de9cc80261963238]::sync::worker_local::WorkerLocal<rustc_middle[a808b96dc0c8b39]::arena::Arena>, &rustc_data_structures[de9cc80261963238]::sync::worker_local::WorkerLocal<rustc_hir[d443c4a01af566e4]::Arena>, rustc_driver_impl[48bdb3468b385e51]::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
44: 0x7fb14be7abd8 - rustc_interface[372b2d608f466254]::interface::run_compiler::<(), rustc_driver_impl[48bdb3468b385e51]::run_compiler::{closure#0}>::{closure#1}
45: 0x7fb14bdae8ce - std[2ade4c2364de62da]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[372b2d608f466254]::util::run_in_thread_with_globals<rustc_interface[372b2d608f466254]::util::run_in_thread_pool_with_globals<rustc_interface[372b2d608f466254]::interface::run_compiler<(), rustc_driver_impl[48bdb3468b385e51]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
46: 0x7fb14bdae6a0 - <std[2ade4c2364de62da]::thread::lifecycle::spawn_unchecked<rustc_interface[372b2d608f466254]::util::run_in_thread_with_globals<rustc_interface[372b2d608f466254]::util::run_in_thread_pool_with_globals<rustc_interface[372b2d608f466254]::interface::run_compiler<(), rustc_driver_impl[48bdb3468b385e51]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[70014f3701156057]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
47: 0x7fb14bdb0446 - <std[2ade4c2364de62da]::sys::thread::unix::Thread>::new::thread_start
48: 0x7fb14569698b - <unknown>
49: 0x7fb14571a9cc - <unknown>
50: 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: rustc 1.94.0-nightly (9b8162963 2026-01-13) running on x86_64-unknown-linux-gnu
note: compiler flags: -Z mir-opt-level=5 -C link-dead-code=true -Z crate-attr=feature(min_generic_const_args) -Z dump-mir-dir=dir
query stack during panic:
#0 [valtree_to_const_val] converting type-level constant value to MIR constant value
#1 [optimized_mir] optimizing MIR for `main`
#2 [items_of_instance] collecting items used by `main`
#3 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
warning: 4 warnings emitted
@rustbot label +F-adt_const_params +F-unsized_const_params +F-generic_const_parameter_types +F-min_generic_const_args