ICE expected leaf, got Value #150734
Description
Code
#![feature(min_generic_const_args, adt_const_params)]
use std::marker::ConstParamTy;
#[derive(Eq, PartialEq, ConstParamTy)]
struct Inner(u32);
#[derive(Eq, PartialEq, ConstParamTy)]
struct Outer(Inner);
fn with_outer<const O: Outer>() -> Outer {
O
}
fn test<const N: u32>() {
with_outer::<{ Outer(Outer(Inner)) }>();
}
fn main() {
test::<5>()
}Meta
rustc --version --verbose:
rustc 1.94.0-nightly (4d73a008e 2026-01-06)
binary: rustc
commit-hash: 4d73a008eaf6ba3ca067a3221e5c00602e33a5f2
commit-date: 2026-01-06
host: x86_64-unknown-linux-gnu
release: 1.94.0-nightly
LLVM version: 21.1.8
Error output
<output>
Backtrace
warning: the feature `min_generic_const_args` is incomplete and may not be safe to use and/or cause compiler crashes
--> a.rs:1:12
|
1 | #![feature(min_generic_const_args, adt_const_params)]
| ^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #132980 <https://github.com/rust-lang/rust/issues/132980> for more information
= note: `#[warn(incomplete_features)]` on by default
error: internal compiler error: /rustc-dev/4d73a008eaf6ba3ca067a3221e5c00602e33a5f2/compiler/rustc_middle/src/ty/consts/valtree.rs:159:40: expected leaf, got Value { ty: u32, valtree: Branch([]) }
thread 'rustc' (2210474) panicked at /rustc-dev/4d73a008eaf6ba3ca067a3221e5c00602e33a5f2/compiler/rustc_middle/src/ty/consts/valtree.rs:159:40:
Box<dyn Any>
stack backtrace:
0: 0x7ff0ef0215b3 - <<std[ddfe47d8d7a1475f]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[a532a151b9e1489e]::fmt::Display>::fmt
1: 0x7ff0ef60fa88 - core[a532a151b9e1489e]::fmt::write
2: 0x7ff0ef037836 - <std[ddfe47d8d7a1475f]::sys::stdio::unix::Stderr as std[ddfe47d8d7a1475f]::io::Write>::write_fmt
3: 0x7ff0eeff71a8 - std[ddfe47d8d7a1475f]::panicking::default_hook::{closure#0}
4: 0x7ff0ef014e43 - std[ddfe47d8d7a1475f]::panicking::default_hook
5: 0x7ff0edffa6ea - std[ddfe47d8d7a1475f]::panicking::update_hook::<alloc[61c3167de76b8e6f]::boxed::Box<rustc_driver_impl[7fdfd38a2830d21c]::install_ice_hook::{closure#1}>>::{closure#0}
6: 0x7ff0ef015122 - std[ddfe47d8d7a1475f]::panicking::panic_with_hook
7: 0x7ff0ee037001 - std[ddfe47d8d7a1475f]::panicking::begin_panic::<rustc_errors[4edd36428cf83490]::ExplicitBug>::{closure#0}
8: 0x7ff0ee027666 - std[ddfe47d8d7a1475f]::sys::backtrace::__rust_end_short_backtrace::<std[ddfe47d8d7a1475f]::panicking::begin_panic<rustc_errors[4edd36428cf83490]::ExplicitBug>::{closure#0}, !>
9: 0x7ff0ee02729f - std[ddfe47d8d7a1475f]::panicking::begin_panic::<rustc_errors[4edd36428cf83490]::ExplicitBug>
10: 0x7ff0ee054d41 - <rustc_errors[4edd36428cf83490]::diagnostic::BugAbort as rustc_errors[4edd36428cf83490]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
11: 0x7ff0ee602ce9 - rustc_middle[5e24b05a5cc6fa51]::util::bug::opt_span_bug_fmt::<rustc_span[eb76c8861bbc8252]::span_encoding::Span>::{closure#0}
12: 0x7ff0ee602e72 - rustc_middle[5e24b05a5cc6fa51]::ty::context::tls::with_opt::<rustc_middle[5e24b05a5cc6fa51]::util::bug::opt_span_bug_fmt<rustc_span[eb76c8861bbc8252]::span_encoding::Span>::{closure#0}, !>::{closure#0}
13: 0x7ff0ee5f3f8b - rustc_middle[5e24b05a5cc6fa51]::ty::context::tls::with_context_opt::<rustc_middle[5e24b05a5cc6fa51]::ty::context::tls::with_opt<rustc_middle[5e24b05a5cc6fa51]::util::bug::opt_span_bug_fmt<rustc_span[eb76c8861bbc8252]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
14: 0x7ff0ebb15e74 - rustc_middle[5e24b05a5cc6fa51]::util::bug::bug_fmt
15: 0x7ff0f071b23a - rustc_const_eval[efa84d9f222e8d9d]::const_eval::valtrees::valtree_to_const_value
16: 0x7ff0f071b5dd - rustc_const_eval[efa84d9f222e8d9d]::const_eval::valtrees::valtree_to_const_value
17: 0x7ff0f071b5dd - rustc_const_eval[efa84d9f222e8d9d]::const_eval::valtrees::valtree_to_const_value
18: 0x7ff0f071adeb - <rustc_const_eval[efa84d9f222e8d9d]::provide::{closure#1} as core[a532a151b9e1489e]::ops::function::FnOnce<(rustc_middle[5e24b05a5cc6fa51]::ty::context::TyCtxt, rustc_middle[5e24b05a5cc6fa51]::ty::consts::valtree::Value)>>::call_once
19: 0x7ff0f071ad96 - rustc_query_impl[6cc0d79cca94585a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[6cc0d79cca94585a]::query_impl::valtree_to_const_val::dynamic_query::{closure#2}::{closure#0}, rustc_middle[5e24b05a5cc6fa51]::query::erase::Erased<[u8; 24usize]>>
20: 0x7ff0f071ad5f - <rustc_query_impl[6cc0d79cca94585a]::query_impl::valtree_to_const_val::dynamic_query::{closure#2} as core[a532a151b9e1489e]::ops::function::FnOnce<(rustc_middle[5e24b05a5cc6fa51]::ty::context::TyCtxt, rustc_middle[5e24b05a5cc6fa51]::ty::consts::valtree::Value)>>::call_once
21: 0x7ff0f071a38c - rustc_query_system[dd105dbe8a673b02]::query::plumbing::try_execute_query::<rustc_query_impl[6cc0d79cca94585a]::DynamicConfig<rustc_query_system[dd105dbe8a673b02]::query::caches::DefaultCache<rustc_middle[5e24b05a5cc6fa51]::ty::consts::valtree::Value, rustc_middle[5e24b05a5cc6fa51]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[6cc0d79cca94585a]::plumbing::QueryCtxt, false>
22: 0x7ff0f071a0a5 - rustc_query_impl[6cc0d79cca94585a]::query_impl::valtree_to_const_val::get_query_non_incr::__rust_end_short_backtrace
23: 0x7ff0f000dfb0 - rustc_monomorphize[971aa2a34d8f8606]::collector::items_of_instance
24: 0x7ff0f000a232 - rustc_query_impl[6cc0d79cca94585a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[6cc0d79cca94585a]::query_impl::items_of_instance::dynamic_query::{closure#2}::{closure#0}, rustc_middle[5e24b05a5cc6fa51]::query::erase::Erased<[u8; 32usize]>>
25: 0x7ff0f030c4d5 - rustc_query_system[dd105dbe8a673b02]::query::plumbing::try_execute_query::<rustc_query_impl[6cc0d79cca94585a]::DynamicConfig<rustc_query_system[dd105dbe8a673b02]::query::caches::DefaultCache<(rustc_middle[5e24b05a5cc6fa51]::ty::instance::Instance, rustc_middle[5e24b05a5cc6fa51]::mir::mono::CollectionMode), rustc_middle[5e24b05a5cc6fa51]::query::erase::Erased<[u8; 32usize]>>, false, false, false>, rustc_query_impl[6cc0d79cca94585a]::plumbing::QueryCtxt, false>
26: 0x7ff0f030c0f3 - rustc_query_impl[6cc0d79cca94585a]::query_impl::items_of_instance::get_query_non_incr::__rust_end_short_backtrace
27: 0x7ff0f0ab8a94 - rustc_monomorphize[971aa2a34d8f8606]::collector::collect_items_rec
28: 0x7ff0f0aba9e7 - rustc_monomorphize[971aa2a34d8f8606]::collector::collect_items_rec
29: 0x7ff0f0aba9e7 - rustc_monomorphize[971aa2a34d8f8606]::collector::collect_items_rec
30: 0x7ff0efa1dae1 - rustc_monomorphize[971aa2a34d8f8606]::collector::collect_crate_mono_items::{closure#1}::{closure#0}
31: 0x7ff0efeb977a - rustc_monomorphize[971aa2a34d8f8606]::partitioning::collect_and_partition_mono_items
32: 0x7ff0f0af45d6 - rustc_query_impl[6cc0d79cca94585a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[6cc0d79cca94585a]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle[5e24b05a5cc6fa51]::query::erase::Erased<[u8; 24usize]>>
33: 0x7ff0f0af459b - <rustc_query_impl[6cc0d79cca94585a]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core[a532a151b9e1489e]::ops::function::FnOnce<(rustc_middle[5e24b05a5cc6fa51]::ty::context::TyCtxt, ())>>::call_once
34: 0x7ff0f0af40f6 - rustc_query_system[dd105dbe8a673b02]::query::plumbing::try_execute_query::<rustc_query_impl[6cc0d79cca94585a]::DynamicConfig<rustc_query_system[dd105dbe8a673b02]::query::caches::SingleCache<rustc_middle[5e24b05a5cc6fa51]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[6cc0d79cca94585a]::plumbing::QueryCtxt, false>
35: 0x7ff0f0af3e9b - rustc_query_impl[6cc0d79cca94585a]::query_impl::collect_and_partition_mono_items::get_query_non_incr::__rust_end_short_backtrace
36: 0x7ff0f09efc8a - rustc_codegen_ssa[8ed2eee97b550a4f]::base::codegen_crate::<rustc_codegen_llvm[da7f0496a594b3e7]::LlvmCodegenBackend>
37: 0x7ff0f09ed77d - <rustc_codegen_llvm[da7f0496a594b3e7]::LlvmCodegenBackend as rustc_codegen_ssa[8ed2eee97b550a4f]::traits::backend::CodegenBackend>::codegen_crate
38: 0x7ff0f0979e8f - <rustc_interface[9980b4cb58bb210e]::queries::Linker>::codegen_and_build_linker
39: 0x7ff0f097749c - <rustc_interface[9980b4cb58bb210e]::passes::create_and_enter_global_ctxt<core[a532a151b9e1489e]::option::Option<rustc_interface[9980b4cb58bb210e]::queries::Linker>, rustc_driver_impl[7fdfd38a2830d21c]::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core[a532a151b9e1489e]::ops::function::FnOnce<(&rustc_session[e5d95afd4a4e27ed]::session::Session, rustc_middle[5e24b05a5cc6fa51]::ty::context::CurrentGcx, alloc[61c3167de76b8e6f]::sync::Arc<rustc_data_structures[fe3ac7cdd49a0dd4]::jobserver::Proxy>, &std[ddfe47d8d7a1475f]::sync::once_lock::OnceLock<rustc_middle[5e24b05a5cc6fa51]::ty::context::GlobalCtxt>, &rustc_data_structures[fe3ac7cdd49a0dd4]::sync::worker_local::WorkerLocal<rustc_middle[5e24b05a5cc6fa51]::arena::Arena>, &rustc_data_structures[fe3ac7cdd49a0dd4]::sync::worker_local::WorkerLocal<rustc_hir[8c63d784b395ad98]::Arena>, rustc_driver_impl[7fdfd38a2830d21c]::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
40: 0x7ff0f085dc58 - rustc_interface[9980b4cb58bb210e]::interface::run_compiler::<(), rustc_driver_impl[7fdfd38a2830d21c]::run_compiler::{closure#0}>::{closure#1}
41: 0x7ff0f070cace - std[ddfe47d8d7a1475f]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[9980b4cb58bb210e]::util::run_in_thread_with_globals<rustc_interface[9980b4cb58bb210e]::util::run_in_thread_pool_with_globals<rustc_interface[9980b4cb58bb210e]::interface::run_compiler<(), rustc_driver_impl[7fdfd38a2830d21c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
42: 0x7ff0f070c8a0 - <std[ddfe47d8d7a1475f]::thread::lifecycle::spawn_unchecked<rustc_interface[9980b4cb58bb210e]::util::run_in_thread_with_globals<rustc_interface[9980b4cb58bb210e]::util::run_in_thread_pool_with_globals<rustc_interface[9980b4cb58bb210e]::interface::run_compiler<(), rustc_driver_impl[7fdfd38a2830d21c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[a532a151b9e1489e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
43: 0x7ff0f070ac78 - <std[ddfe47d8d7a1475f]::sys::thread::unix::Thread>::new::thread_start
44: 0x7ff0ea09698b - <unknown>
45: 0x7ff0ea11a9cc - <unknown>
46: 0x0 - <unknown>
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/im/rustc-ice-2026-01-06T20_55_29-2210445.txt` to your bug report
note: rustc 1.94.0-nightly (4d73a008e 2026-01-06) running on x86_64-unknown-linux-gnu
query stack during panic:
#0 [valtree_to_const_val] converting type-level constant value to MIR constant value
#1 [items_of_instance] collecting items used by `with_outer::<ValTree(Branch([ValTree(Branch([ValTree(Branch([]): Inner)]): Outer)]): Outer)>`
#2 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
error: aborting due to 1 previous error; 1 warning emitted