delayed bug: Missing value for constant, but no error reported?

[SparkyPotato]

Code

#![feature(generic_const_exprs)]

trait NodeIndex: Copy {}

struct Interface<'a, T: NodeIndex> {
    borrow: &'a (),
    _phantom: std::marker::PhantomData<fn() -> T>,
}

trait Component: 'static {
    type NodeIndex: NodeIndex;
    fn exec(&mut self, nodes: Interface<'_, Self::NodeIndex>);
}

trait SimpleComponent: 'static {
    const NODES: usize;
    fn exec(&mut self, input: [f32; Self::NODES]) -> [f32; Self::NODES];
}

#[derive(Copy, Clone)]
struct Node<const NODES: usize>(u8);
impl<const NODES: usize> NodeIndex for Node<NODES> {}

impl<T: SimpleComponent> Component for T 
where
    [(); T::NODES]:, // This where bound causes the ICE
{
    type NodeIndex = Node<{T::NODES}>;
    fn exec(&mut self, nodes: Interface<'_, Self::NodeIndex>) { /* ICEs even if the function is empty */ }
}

The above code doesn't reproduce the error, but has a similar structure to what causes the ICE in a larger codebase. Even in the codebase where it ICEs, creating a trait with the exact same definition (call it ComponentCopy), and then replacing the impl Component for T with:

- impl<T: SimpleComponent> Component for T where [(); T::NODES]: { ... }
+ impl<T: SimpleComponent> ComponentCopy for T where [(); T::NODES]: { /* same as above */ }
+ impl<T: ComponentCopy> Component for T { /* forward the assoc. type and method */ }

doesn't cause the ICE anymore.

There isn't even a span attached to the delayed error.

Meta

rustc --version --verbose:

rustc 1.82.0-nightly (28a58f2fa 2024-07-31)
binary: rustc
commit-hash: 28a58f2fa7f0c46b8fab8237c02471a915924fe5
commit-date: 2024-07-31
host: x86_64-pc-windows-msvc
release: 1.82.0-nightly
LLVM version: 19.1.0

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

Backtrace

``` delayed bug: Missing value for constant, but no error reported? 0: std::backtrace_rs::backtrace::dbghelp64::trace at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\std\src\..\..\backtrace\src\backtrace\dbghelp64.rs:91 1: std::backtrace_rs::backtrace::trace_unsynchronized at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\std\src\..\..\backtrace\src\backtrace\mod.rs:66 2: std::backtrace::Backtrace::create at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\std\src\backtrace.rs:331 3: std::backtrace::Backtrace::capture at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\std\src\backtrace.rs:296 4: ::steal_fulfilled_expectation_ids 5: ::emit_diagnostic 6: ::emit_producing_guarantee 7: >::decorate_lint 8: rustc_trait_selection::traits::const_evaluatable::is_const_evaluatable 9: ::evaluate_root_obligation 10: rustc_traits::evaluate_obligation::evaluate_obligation 11: rustc_query_impl::plumbing::query_key_hash_verify_all 12: rustc_ty_utils::ty::self_ty_of_trait_impl_enabling_order_dep_trait_object_hack 13: rustc_query_impl::plumbing::query_key_hash_verify_all 14: ::evaluate_obligation_no_overflow 15: ::predicate_may_hold 16: ::load_operand 17: rustc_hir_typeck::method::probe::method_autoderef_steps 18: rustc_hir_typeck::method::probe::method_autoderef_steps 19: rustc_hir_typeck::typeck 20: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 21: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 22: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 23: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 24: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 25: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 26: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 27: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 28: rustc_hir_typeck::typeck 29: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 30: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 31: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 32: rustc_hir_typeck::typeck 33: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 34: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 35: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 36: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 37: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 38: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 39: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 40: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 41: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 42: <::deduce_closure_signature_from_predicates::MentionsTy as rustc_type_ir::visit::TypeVisitor>::visit_ty 43: rustc_hir_typeck::typeck 44: rustc_hir_typeck::typeck 45: rustc_query_impl::plumbing::query_key_hash_verify_all 46: rustc_ty_utils::ty::self_ty_of_trait_impl_enabling_order_dep_trait_object_hack 47: rustc_query_impl::plumbing::query_key_hash_verify_all 48: ::borrow 49: rustc_hir_analysis::check_crate 50: rustc_interface::passes::analysis 51: ::write_str 52: rustc_ty_utils::ty::adt_sized_constraint 53: rustc_query_impl::query_system 54: _wpgmptr 55: _wpgmptr 56: _wpgmptr 57: alloc::boxed::impl$48::call_once at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\alloc\src\boxed.rs:2148 58: alloc::boxed::impl$48::call_once at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\alloc\src\boxed.rs:2148 59: std::sys::pal::windows::thread::impl$0::new::thread_start at /rustc/28a58f2fa7f0c46b8fab8237c02471a915924fe5/library\std\src\sys\pal\windows\thread.rs:55 60: BaseThreadInitThunk 61: RtlUserThreadStart rustc version: 1.82.0-nightly (28a58f2fa 2024-07-31) platform: x86_64-pc-windows-msvc ```

[matthiaskrgr]

probably a duplicate of https://github.com/rust-lang/rust/issues/110378