rust-lang / rust-lang/rust

internal compiler error: Missing value for constant, but no error reported?

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C-bug F-generic_const_exprs I-ICE P-low S-bug-has-test S-has-mcve T-compiler
Dominant language
Rust
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Description

Code
#![feature(generic_const_exprs)]

struct Struct;
trait Trait {
    const CONST: usize = 0;
}
impl Trait for Struct {}

fn f_<T>() {}

trait DynTrait {
    fn f(&self);
}

impl<T> DynTrait for T
where
    T: Trait,
    [(); T::CONST]:,
{
    fn f(&self) {
        f_::<T>()
    }
}

fn main() {
    Box::new(Struct).f();
}
Meta

rustc --version --verbose:

rustc 1.85.0-nightly (9e136a30a 2024-12-19)
binary: rustc
commit-hash: 9e136a30a965bf4e63f03095c57df7257bf96fd6
commit-date: 2024-12-19
host: x86_64-pc-windows-msvc
release: 1.85.0-nightly
LLVM version: 19.1.6
Error output
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: Missing value for constant, but no error reported?
  |
  = note: delayed at compiler\rustc_trait_selection\src\traits\const_evaluatable.rs:74:68 - disabled backtrace

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 `C:\Users\agero\Documents\projets\ramsey-dl\rustc-ice-2024-12-21T13_27_24-551924.txt` to your bug report

note: compiler flags: --crate-type bin -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
warning: `reproduce_crash` (bin "reproduce_crash") generated 2 warnings
error: could not compile `reproduce_crash` (bin "reproduce_crash"); 2 warnings emitted

Caused by:
  process didn't exit successfully: `C:\Users\agero\.rustup\toolchains\nightly-2024-12-20-x86_64-pc-windows-msvc\bin\rustc.exe --crate-name reproduce_crash --edition=2024 src\main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=119 --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 --check-cfg cfg(docsrs) --check-cfg "cfg(feature, values())" -C metadata=f41a790c0ca691fa --out-dir C:\Users\agero\Documents\projets\ramsey-dl\target\debug\deps -C incremental=C:\Users\agero\Documents\projets\ramsey-dl\target\debug\incremental -L dependency=C:\Users\agero\Documents\projets\ramsey-dl\target\debug\deps` (exit code: 101)
Backtrace 

delayed bug: Missing value for constant, but no error reported?
   0: std::backtrace_rs::backtrace::dbghelp64::trace
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\std\src\..\..\backtrace\src\backtrace\dbghelp64.rs:91
   1: std::backtrace_rs::backtrace::trace_unsynchronized
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66
   2: std::backtrace::Backtrace::create
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\std\src\backtrace.rs:331
   3: std::backtrace::Backtrace::capture
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\std\src\backtrace.rs:296
   4: <rustc_errors::DiagCtxtHandle>::flush_delayed
   5: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
   6: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
   7: <hashbrown::raw::RawTable<usize>>::reserve_rehash::<indexmap::map::core::get_hash<rustc_middle::ty::region::Region, ()>::{closure#0}>
   8: rustc_trait_selection::traits::const_evaluatable::is_const_evaluatable
   9: <rustc_trait_selection::traits::select::SelectionContext>::evaluate_root_obligation
  10: rustc_traits::evaluate_obligation::evaluate_obligation
  11: rustc_query_impl::plumbing::query_key_hash_verify_all
  12: RINvNtNtCsQCwQoe5Jo1_18rustc_query_system5query8plumbing17try_execute_queryINtCs4qpE3tcYOsg_16rustc_query_impl13DynamicConfigINtNtB4_6caches12DefaultCacheINtNtCs4xXlGRTpLhK_13rustc_type_ir9canonical19CanonicalQueryInputNtNtNtCsabap53b4qYL_12rustc_middle2ty
  13: rustc_query_impl::plumbing::query_key_hash_verify_all
  14: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::evaluate_obligation_no_overflow
  15: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt>::predicate_may_hold
  16: <alloc::raw_vec::RawVec<rustc_hir_typeck::method::probe::Candidate>>::grow_one
  17: rustc_hir_typeck::method::probe::method_autoderef_steps
  18: rustc_hir_typeck::method::probe::method_autoderef_steps
  19: rustc_hir_typeck::typeck
  20: <<rustc_hir_typeck::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor<rustc_middle::ty::context::TyCtxt>>::visit_ty
  21: <<rustc_hir_typeck::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor<rustc_middle::ty::context::TyCtxt>>::visit_ty
  22: <<rustc_hir_typeck::fn_ctxt::FnCtxt>::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor<rustc_middle::ty::context::TyCtxt>>::visit_ty
  23: rustc_hir_typeck::typeck
  24: rustc_hir_typeck::typeck
  25: rustc_query_impl::plumbing::query_key_hash_verify_all
  26: RINvNtNtCsQCwQoe5Jo1_18rustc_query_system5query8plumbing17try_execute_queryINtCs4qpE3tcYOsg_16rustc_query_impl13DynamicConfigINtNtCsl5fsRWpEAH1_21rustc_data_structures9vec_cache8VecCacheNtNtCshwu7G5mdp9_10rustc_span6def_id10LocalDefIdINtNtNtCsabap53b4qYL_1
  27: rustc_query_impl::plumbing::query_key_hash_verify_all
  28: RINvMs6_NtCsfSe2htisICB_9hashbrown3rawINtB6_8RawTablejE14reserve_rehashNCINvNtNtCsggveAX2leLM_8indexmap3map4core8get_hashTNtNtNtCsabap53b4qYL_12rustc_middle2ty9predicate6ClauseNtNtCshwu7G5mdp9_10rustc_span13span_encoding4SpanEuE0ECs4Qtc6Yytiwo_18rustc_hir_
  29: rustc_hir_analysis::check_crate
  30: rustc_interface::passes::resolver_for_lowering_raw
  31: rustc_interface::passes::analysis
  32: <alloc::sync::Arc<rustc_session::cstore::CrateSource>>::drop_slow
  33: RINvNtNtCsQCwQoe5Jo1_18rustc_query_system5query8plumbing17try_execute_queryINtCs4qpE3tcYOsg_16rustc_query_impl13DynamicConfigINtNtB4_6caches11SingleCacheINtNtNtCsabap53b4qYL_12rustc_middle5query5erase6ErasedAhj0_EEKb0_KB3r_KB3r_ENtNtB1e_8plumbing9QueryCtxt
  34: rustc_query_impl::query_system
  35: RINvNtNtCs8RqLblBvRGN_3std3sys9backtrace28___rust_begin_short_backtraceNCNCNCINvMNtB6_6threadNtB1h_7Builder16spawn_unchecked_INtNtCsjGo8snB8Fhu_5alloc5boxed3BoxDINtNtNtCs6jWqyqrNxNm_4core3ops8function6FnOnceuEp6OutputuNtNtB2G_6marker4SendEL_EuEs_000uECs36X
  36: RINvNtNtCs8RqLblBvRGN_3std3sys9backtrace28___rust_begin_short_backtraceNCNCNCINvMNtB6_6threadNtB1h_7Builder16spawn_unchecked_INtNtCsjGo8snB8Fhu_5alloc5boxed3BoxDINtNtNtCs6jWqyqrNxNm_4core3ops8function6FnOnceuEp6OutputuNtNtB2G_6marker4SendEL_EuEs_000uECs36X
  37: RINvNtNtCs8RqLblBvRGN_3std3sys9backtrace28___rust_begin_short_backtraceNCNCINvNtCsjzFb9IgEjHS_15rustc_interface4util26run_in_thread_with_globalsNCINvB1e_31run_in_thread_pool_with_globalsNCINvNtB1g_9interface12run_compileruNCNvCs36XBSsR0b4J_17rustc_driver_i
  38: RINvNtNtCs8RqLblBvRGN_3std3sys9backtrace28___rust_begin_short_backtraceNCNCNCINvMNtB6_6threadNtB1h_7Builder16spawn_unchecked_INtNtCsjGo8snB8Fhu_5alloc5boxed3BoxDINtNtNtCs6jWqyqrNxNm_4core3ops8function6FnOnceuEp6OutputuNtNtB2G_6marker4SendEL_EuEs_000uECs36X
  39: alloc::boxed::impl$28::call_once
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\alloc\src\boxed.rs:1970
  40: alloc::boxed::impl$28::call_once
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\alloc\src\boxed.rs:1970
  41: std::sys::pal::windows::thread::impl$0::new::thread_start
             at /rustc/9e136a30a965bf4e63f03095c57df7257bf96fd6/library\std\src\sys\pal\windows\thread.rs:55
  42: BaseThreadInitThunk
  43: RtlUserThreadStart



rustc version: 1.85.0-nightly (9e136a30a 2024-12-19)
platform: x86_64-pc-windows-msvc

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.

Research direction

Start by compiling the provided generic_const_exprs reproducer with the reported nightly and inspect rustc_trait_selection/src/traits/const_evaluatable.rs at the delayed-bug location. Trace the const-evaluatability path shown in the backtrace and add or update coverage for this example. Done means the reproducer no longer triggers an internal compiler error and produces an appropriate result.

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
Stale
Clarity
Mostly clear
Newbie friendliness
38/100

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