ICE: invalid Res for const path

[matthiaskrgr]

auto-reduced (treereduce-rust):

//@compile-flags: --crate-type=lib
#![feature(min_generic_const_args)]
mod m {
    pub struct Uuid(());

    impl Uuid {
        pub fn encode_buffer() -> [u8; Uuid] {
            []
        }
    }
}

original:

mod m {
    pub struct Uuid(());

    impl Uuid {
        pub fn encode_buffer() -> [u8; Uuid] {
            []
        }
    }
    const LENGTH: usize = 0;
}

pub use m::Uuid;

Version information

rustc 1.86.0-nightly (9e48dfe5e 2025-02-01)
binary: rustc
commit-hash: 9e48dfe5e0d5ec1b064b5d25504948ede0ec9b53
commit-date: 2025-02-01
host: x86_64-unknown-linux-gnu
release: 1.86.0-nightly
LLVM version: 19.1.7

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcrate-attr=feature(min_generic_const_args) --crate-type=lib

Program output

warning: the feature `min_generic_const_args` is incomplete and may not be safe to use and/or cause compiler crashes
 --> <crate attribute>:1:9
  |
1 | feature(min_generic_const_args)
  |         ^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #132980 <https://github.com/rust-lang/rust/issues/132980> for more information
  = note: `#[warn(incomplete_features)]` on by default

warning: struct `Uuid` is never constructed
 --> /tmp/icemaker_global_tempdir.pnE6EpSQ5yN3/rustc_testrunner_tmpdir_reporting.8KFeOkEvN674/mvce.rs:2:16
  |
2 |     pub struct Uuid(());
  |                ^^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: associated function `encode_buffer` is never used
 --> /tmp/icemaker_global_tempdir.pnE6EpSQ5yN3/rustc_testrunner_tmpdir_reporting.8KFeOkEvN674/mvce.rs:5:16
  |
4 |     impl Uuid {
  |     --------- associated function in this implementation
5 |         pub fn encode_buffer() -> [u8; Uuid] {
  |                ^^^^^^^^^^^^^

warning: 3 warnings emitted

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: invalid Res for const path
 --> /tmp/icemaker_global_tempdir.pnE6EpSQ5yN3/rustc_testrunner_tmpdir_reporting.8KFeOkEvN674/mvce.rs:5:40
  |
5 |         pub fn encode_buffer() -> [u8; Uuid] {
  |                                        ^^^^
  |
note: delayed at compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs:2202:27
         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, &str>
         4: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_const_arg.cold
         5: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_ty
         6: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_fn_ty
         7: rustc_hir_analysis::collect::lower_fn_sig_recovering_infer_ret_ty
         8: rustc_hir_analysis::collect::fn_sig
         9: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::fn_sig::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>>
        10: <rustc_query_impl::query_impl::fn_sig::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId)>>::call_once
        11: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        12: rustc_query_impl::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace
        13: <rustc_hir_analysis::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_impl_item
        14: rustc_hir_analysis::check::wfcheck::check_well_formed
        15: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        16: 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; 1]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        17: rustc_query_impl::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
        18: rustc_hir_analysis::check::wfcheck::check_mod_type_wf
        19: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 1]>>
        20: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalModDefId, rustc_middle::query::erase::Erased<[u8; 1]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        21: rustc_query_impl::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
        22: rustc_hir_analysis::check_crate
        23: rustc_interface::passes::run_required_analyses
        24: rustc_interface::passes::analysis
        25: 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]>>
        26: 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, false>
        27: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        28: 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}
        29: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        30: 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}, ()>
        31: <<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}
        32: std::sys::pal::unix::thread::Thread::new::thread_start
        33: <unknown>
        34: <unknown>
 --> /tmp/icemaker_global_tempdir.pnE6EpSQ5yN3/rustc_testrunner_tmpdir_reporting.8KFeOkEvN674/mvce.rs:5:40
  |
5 |         pub fn encode_buffer() -> [u8; Uuid] {
  |                                        ^^^^

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 1.86.0-nightly (9e48dfe5e 2025-02-01) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z crate-attr=feature(min_generic_const_args) --crate-type lib -Z dump-mir-dir=dir

query stack during panic:
end of query stack

@rustbot label +F-min_generic_const_args

[matthiaskrgr]

#![feature(min_generic_const_args)]
pub struct S();

impl S {
    pub fn f() -> [u8; S] {
        []
    }
}

pub fn main() {}