[ICE]: `expected ConstKind::Value, got AliasConst` / `got {const error}`
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Nobody has claimed this yet.
C-bug
F-generic_const_args
F-min_generic_const_args
I-ICE
needs-triage
T-compiler
- Dominant language
- Rust
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- 119k
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Description
auto-reduced (treereduce-rust):
#![feature(macroless_generic_const_args)]
#![feature(generic_const_args)]
const C_INNER: (*const u8, u8) = (C, 0);
fn foo2(x: *const u8) {
match (x, 1) {
C_INNER => {}
};
}
original:
#![feature(macroless_generic_const_args)]
#![feature(generic_const_args, min_generic_const_args)]
const C: *const u8 = &0;
const C_INNER: (*const u8, u8) = (C, 0);
fn foo2(x: *const u8) {
match (x, 1) {
C_INNER => {}
};
}
fn main() {}
Version information
rustc 1.100.0-nightly (da47efd27 2026-09-06)
binary: rustc
commit-hash: da47efd27287edb02eed0b5a178a165c8f258e37
commit-date: 2026-09-06
host: x86_64-unknown-linux-gnu
release: 1.100.0-nightly
LLVM version: 23.1.1
Possibly related line of code:
https://github.com/rust-lang/rust/blob/da47efd27287edb02eed0b5a178a165c8f258e37/compiler/rustc_middle/src/ty/consts.rs#L250-L262
Command:
/home/matthias/.rustup/toolchains/master/bin/rustc
Program output
error[E0425]: cannot find value `C` in this scope
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:4:35
|
4 | const C_INNER: (*const u8, u8) = (C, 0);
| ^ not found in this scope
error: `generic_const_args` requires `min_generic_const_args` to be enabled
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:2:12
|
2 | #![feature(generic_const_args)]
| ^^^^^^^^^^^^^^^^^^
|
= help: enable all of these features
error: `macroless_generic_const_args` requires `min_generic_const_args` to be enabled
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:1:12
|
1 | #![feature(macroless_generic_const_args)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: enable all of these features
warning: the feature `macroless_generic_const_args` is incomplete and may not be safe to use and/or cause compiler crashes
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:1:12
|
1 | #![feature(macroless_generic_const_args)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: see issue #159006 <https://github.com/rust-lang/rust/issues/159006> for more information
= note: `#[warn(incomplete_features)]` on by default
warning: the feature `generic_const_args` is incomplete and may not be safe to use and/or cause compiler crashes
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:2:12
|
2 | #![feature(generic_const_args)]
| ^^^^^^^^^^^^^^^^^^
|
= note: see issue #151972 <https://github.com/rust-lang/rust/issues/151972> for more information
error[E0601]: `main` function not found in crate `mvce`
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:9:2
|
9 | }
| ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs`
error[E0741]: `(*const u8, u8)` can't be used as a const parameter type
--> /tmp/icemaker_global_tempdir.5ErorvnDhU35/rustc_testrunner_tmpdir_reporting.pgzBU5UhoO9P/mvce.rs:4:16
|
4 | const C_INNER: (*const u8, u8) = (C, 0);
| ^^^^^^^^^^^^^^^
|
= note: `*const u8` must implement `ConstParamTy_`, but it does not
error: internal compiler error: /rustc-dev/da47efd27287edb02eed0b5a178a165c8f258e37/compiler/rustc_middle/src/ty/consts.rs:256:18: expected ConstKind::Value, got {const error}
thread 'rustc' (2310463) panicked at /rustc-dev/da47efd27287edb02eed0b5a178a165c8f258e37/compiler/rustc_middle/src/ty/consts.rs:256:18:
Box<dyn Any>
stack backtrace:
0: 0x7f30c98bde86 - <<std[7b8d936ff0591b4d]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[1338a38dbbf8640b]::fmt::Display>::fmt
1: 0x7f30ca00829d - core[1338a38dbbf8640b]::fmt::write
2: 0x7f30c98d2f5c - <std[7b8d936ff0591b4d]::sys::stdio::unix::Stderr as core[1338a38dbbf8640b]::io::write::Write>::write_fmt
3: 0x7f30c989072a - std[7b8d936ff0591b4d]::panicking::default_hook::{closure#0}
4: 0x7f30c98b2183 - std[7b8d936ff0591b4d]::panicking::default_hook
5: 0x7f30c87fc55f - std[7b8d936ff0591b4d]::panicking::update_hook::<alloc[c8046bf86c4c1cc9]::boxed::Box<rustc_driver_impl[542a485098bab399]::install_ice_hook::{closure#1}>>::{closure#0}
6: 0x7f30c98b2622 - std[7b8d936ff0591b4d]::panicking::panic_with_hook
7: 0x7f30c882ae04 - std[7b8d936ff0591b4d]::panicking::begin_panic::<rustc_errors[a20f047156ee2e30]::ExplicitBug>::{closure#0}
8: 0x7f30c8823916 - std[7b8d936ff0591b4d]::sys::backtrace::__rust_end_short_backtrace::<std[7b8d936ff0591b4d]::panicking::begin_panic<rustc_errors[a20f047156ee2e30]::ExplicitBug>::{closure#0}, !>
9: 0x7f30c88238cb - std[7b8d936ff0591b4d]::panicking::begin_panic::<rustc_errors[a20f047156ee2e30]::ExplicitBug>
10: 0x7f30c88366d1 - <rustc_errors[a20f047156ee2e30]::diagnostic::BugAbort as rustc_errors[a20f047156ee2e30]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
11: 0x7f30c8ddc9b9 - rustc_middle[3307db12b2d0bcfe]::util::bug::opt_span_bug_fmt::<rustc_span[be290dbee5d4923]::span_encoding::Span>::{closure#0}
12: 0x7f30c8ddcdf2 - rustc_middle[3307db12b2d0bcfe]::ty::context::tls::with_opt::<rustc_middle[3307db12b2d0bcfe]::util::bug::opt_span_bug_fmt<rustc_span[be290dbee5d4923]::span_encoding::Span>::{closure#0}, !>::{closure#0}
13: 0x7f30c8dc8060 - rustc_middle[3307db12b2d0bcfe]::ty::context::tls::with_context_opt::<rustc_middle[3307db12b2d0bcfe]::ty::context::tls::with_opt<rustc_middle[3307db12b2d0bcfe]::util::bug::opt_span_bug_fmt<rustc_span[be290dbee5d4923]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
14: 0x7f30c5aa21c4 - rustc_middle[3307db12b2d0bcfe]::util::bug::bug_fmt
15: 0x7f30c8df981a - <rustc_middle[3307db12b2d0bcfe]::ty::consts::Const>::to_value
16: 0x7f30cb20e0e6 - <rustc_mir_build[5b5ed771c07fcc6e]::thir::pattern::const_to_pat::ConstToPat>::valtree_to_pat
17: 0x7f30cb20ce45 - <rustc_mir_build[5b5ed771c07fcc6e]::thir::pattern::PatCtxt>::const_to_pat
18: 0x7f30ca7f19a7 - <rustc_mir_build[5b5ed771c07fcc6e]::thir::pattern::PatCtxt>::lower_pat_expr
19: 0x7f30ca7f35ec - <rustc_mir_build[5b5ed771c07fcc6e]::thir::pattern::PatCtxt>::lower_pattern
20: 0x7f30ca7f2454 - rustc_mir_build[5b5ed771c07fcc6e]::thir::pattern::pat_from_hir::{closure#0}
21: 0x7f30ca7fb230 - <rustc_mir_build[5b5ed771c07fcc6e]::thir::cx::ThirBuildCx>::mirror_expr
22: 0x7f30ca7f83e6 - <rustc_mir_build[5b5ed771c07fcc6e]::thir::cx::ThirBuildCx>::mirror_block
23: 0x7f30ca7fa2ae - <rustc_mir_build[5b5ed771c07fcc6e]::thir::cx::ThirBuildCx>::mirror_expr
24: 0x7f30ca7e67d4 - rustc_mir_build[5b5ed771c07fcc6e]::thir::cx::thir_body
25: 0x7f30ca7e5b12 - rustc_query_impl[a795fc8e0dec0451]::query_vtables::thir_body::invoke_provider_fn::__rust_begin_short_backtrace
26: 0x7f30ca6821cc - rustc_query_impl[a795fc8e0dec0451]::execution::try_execute_query::<rustc_data_structures[a20bf6f691e5a6d4]::vec_cache::VecCache<rustc_span[be290dbee5d4923]::def_id::LocalDefId, rustc_middle[3307db12b2d0bcfe]::query::erase::ErasedData<[u8; 16usize]>, rustc_middle[3307db12b2d0bcfe]::dep_graph::graph::DepNodeIndex>, false>
27: 0x7f30ca681ba7 - rustc_query_impl[a795fc8e0dec0451]::query_vtables::thir_body::execute_query_non_incr::__rust_end_short_backtrace
28: 0x7f30ca7dd94d - rustc_mir_build[5b5ed771c07fcc6e]::check_unsafety::check_unsafety
29: 0x7f30ca7cb6d1 - rustc_query_impl[a795fc8e0dec0451]::execution::try_execute_query::<rustc_data_structures[a20bf6f691e5a6d4]::vec_cache::VecCache<rustc_span[be290dbee5d4923]::def_id::LocalDefId, rustc_middle[3307db12b2d0bcfe]::query::erase::ErasedData<[u8; 0usize]>, rustc_middle[3307db12b2d0bcfe]::dep_graph::graph::DepNodeIndex>, false>
30: 0x7f30ca7cb455 - rustc_query_impl[a795fc8e0dec0451]::query_vtables::check_unsafety::execute_query_non_incr::__rust_end_short_backtrace
31: 0x7f30ca7ca253 - <rustc_middle[3307db12b2d0bcfe]::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface[55d539fc721ed361]::passes::run_required_analyses::{closure#2}::{closure#0}>::{closure#0}
32: 0x7f30ca7c964e - rustc_interface[55d539fc721ed361]::passes::analysis
33: 0x7f30cb23084a - rustc_query_impl[a795fc8e0dec0451]::execution::try_execute_query::<rustc_middle[3307db12b2d0bcfe]::query::caches::SingleCache<rustc_middle[3307db12b2d0bcfe]::query::erase::ErasedData<[u8; 0usize]>>, false>
34: 0x7f30cb23062b - rustc_query_impl[a795fc8e0dec0451]::query_vtables::analysis::execute_query_non_incr::__rust_end_short_backtrace
35: 0x7f30cb31f78c - rustc_interface[55d539fc721ed361]::interface::run_compiler::<(), rustc_driver_impl[542a485098bab399]::run_compiler::{closure#0}>::{closure#2}
36: 0x7f30cb42f564 - std[7b8d936ff0591b4d]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[55d539fc721ed361]::util::run_in_thread_with_globals<rustc_interface[55d539fc721ed361]::util::run_in_thread_pool_with_globals<rustc_interface[55d539fc721ed361]::interface::run_compiler<(), rustc_driver_impl[542a485098bab399]::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
37: 0x7f30cb42f30b - <std[7b8d936ff0591b4d]::thread::lifecycle::spawn_unchecked<rustc_interface[55d539fc721ed361]::util::run_in_thread_with_globals<rustc_interface[55d539fc721ed361]::util::run_in_thread_pool_with_globals<rustc_interface[55d539fc721ed361]::interface::run_compiler<(), rustc_driver_impl[542a485098bab399]::run_compiler::{closure#0}>::{closure#2}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[1338a38dbbf8640b]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
38: 0x7f30cb42cd47 - <std[7b8d936ff0591b4d]::sys::thread::unix::Thread>::new::thread_start
39: 0x7f30c44980a2 - <unknown>
40: 0x7f30c452080c - <unknown>
41: 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: rustc 1.100.0-nightly (da47efd27 2026-09-06) running on x86_64-unknown-linux-gnu
query stack during panic:
#0 [thir_body] building THIR for `foo2`
#1 [check_unsafety] unsafety-checking `foo2`
#2 [analysis] running analysis passes on crate `mvce`
end of query stack
error: aborting due to 6 previous errors; 2 warnings emitted
Some errors have detailed explanations: E0425, E0601, E0741.
For more information about an error, try `rustc --explain E0425`.
@rustbot label +F-macroless_generic_const_args +F-generic_const_args +F-min_generic_const_args
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the reduced reproducer in /tmp/reports/a.rs and inspect compiler/rustc_middle/src/ty/consts.rs around lines 250-262, following the THIR pattern path shown in the query stack. Run the reproducer with the reported nightly features and rustc command; done means this input produces diagnostics without an internal compiler error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 50/100