ICE: unexpected ambiguity: CanonicalQueryInput - broken MIR

[konnorandrews]

Code

I tried to minimize the code but ended up with quite a lot. Clone the below repo and run cargo check.

https://gitlab.com/konnorandrews/supply/-/tree/rustc-ice-ambiguity?ref_type=heads

Meta

rustc --version --verbose:

rustc 1.87.0 (17067e9ac 2025-05-09)
binary: rustc
commit-hash: 17067e9ac6d7ecb70e50f92c1944e545188d2359
commit-date: 2025-05-09
host: x86_64-unknown-linux-gnu
release: 1.87.0
LLVM version: 20.1.1

Also tested on beta and nightly with same error.

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: unexpected ambiguity: CanonicalQueryInput { canonical: Canonical { value: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [Binder { value: TraitPredicate(<T as ToProviderRef<'_>>, polarity:Positive), bound_vars: [] }, Binder { value: TraitPredicate(<T as std::marker::Sized>, polarity:Positive), bound_vars: [] }] }, value: AliasTy { args: [Value<i32, Infer, ty_tag::DefaultGroup>, ty_tag::lifetime_list::Lt<'^1, ty_tag::lifetime_list::Lt<'^2, Alias(Projection, AliasTy { args: [T/#1, '^2, &'^3 T/#1], def_id: DefId(0:52 ~ supply[8b9a]::ToProviderRef::LifetimesRef), .. })>>], def_id: DefId(0:38 ~ supply[8b9a]::RequestWithArg::Output), .. } }, max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }, CanonicalVarInfo { kind: Region(U0) }, CanonicalVarInfo { kind: Region(U0) }, CanonicalVarInfo { kind: Region(U0) }] }, typing_mode: Analysis { defining_opaque_types: [] } } Canonical { value: QueryResponse { var_values: CanonicalVarValues { var_values: ['^0, '^1, '^2, '^3] }, region_constraints: QueryRegionConstraints { outlives: [(OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^1, '^1), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate('^2, '^2), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<ty_tag::num::NZero>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NZero, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::lifetime_list::projection::NRange<ty_tag::num::NOne<ty_tag::num::NZero>, ty_tag::num::NOne<ty_tag::num::NZero>>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<ty_tag::num::NZero>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<ty_tag::num::NOne<Alias(Projection, AliasTy { args: [Alias(Projection, AliasTy { args: [T/#1, '^2, &'^3 T/#1], def_id: DefId(0:52 ~ supply[8b9a]::ToProviderRef::LifetimesRef), .. })], def_id: DefId(20:902 ~ ty_tag[fb59]::lifetime_list::LifetimeListType::Len), .. })>>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<Alias(Projection, AliasTy { args: [Alias(Projection, AliasTy { args: [T/#1, '^2, &'^3 T/#1], def_id: DefId(0:52 ~ supply[8b9a]::ToProviderRef::LifetimesRef), .. })], def_id: DefId(20:902 ~ ty_tag[fb59]::lifetime_list::LifetimeListType::Len), .. })>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<ty_tag::num::NZero>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NZero, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::external_tags::core::I32, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::lifetime_list::projection::NRange<ty_tag::num::NOne<ty_tag::num::NZero>, ty_tag::num::NOne<ty_tag::num::NZero>>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<ty_tag::num::NZero>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NOne<ty_tag::num::NZero>, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::num::NZero, 'static), BoringNoLocation), (OutlivesPredicate(ty_tag::lifetime_list::projection::NRange<ty_tag::num::NOne<ty_tag::num::NZero>, ty_tag::num::NOne<ty_tag::num::NZero>>, 'static), BoringNoLocation), (OutlivesPredicate(Alias(Projection, AliasTy { args: [Alias(Projection, AliasTy { args: [T/#1, '^2, &'^3 T/#1], def_id: DefId(0:52 ~ supply[8b9a]::ToProviderRef::LifetimesRef), .. })], def_id: DefId(20:902 ~ ty_tag[fb59]::lifetime_list::LifetimeListType::Len), .. }), 'static), BoringNoLocation)] }, certainty: Ambiguous, opaque_types: [], value: NormalizationResult { normalized_ty: std::option::Option<i32> } }, max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }, CanonicalVarInfo { kind: Region(U0) }, CanonicalVarInfo { kind: Region(U0) }, CanonicalVarInfo { kind: Region(U0) }] }
  |
  = note: delayed at compiler/rustc_trait_selection/src/traits/query/normalize.rs:287:30 - disabled backtrace

error: internal compiler error: error performing operation: fully_perform
  --> src/lib.rs:14:5
   |
14 |     x.to_provider_ref().request::<Value<i32>>();
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: delayed at /rustc/17067e9ac6d7ecb70e50f92c1944e545188d2359/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:87:25 - disabled backtrace
  --> src/lib.rs:14:5
   |
14 |     x.to_provider_ref().request::<Value<i32>>();
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: internal compiler error: broken MIR in DefId(0:26 ~ supply[8b9a]::pretty_print) (Terminator { source_info: SourceInfo { span: src/lib.rs:14:5: 14:48 (#0), scope: scope[0] }, kind: _2 = <<T as ToProviderRef<'_, &T>>::ProviderRef as RequestExt>::request::<'_, Value<i32>>(move _3) -> [return: bb2, unwind: bb3] }): call dest mismatch (std::option::Option<i32> <- Alias(Projection, AliasTy { args: [Value<i32, Infer, ty_tag::DefaultGroup>, ty_tag::lifetime_list::Lt<'?8, Alias(Projection, AliasTy { args: [Alias(Projection, AliasTy { args: [T/#1, '?6, &'?7 T/#1], def_id: DefId(0:53 ~ supply[8b9a]::ToProviderRef::ProviderRef), .. })], def_id: DefId(0:47 ~ supply[8b9a]::HasLifetimes::Lifetimes), .. })>], def_id: DefId(0:38 ~ supply[8b9a]::RequestWithArg::Output), .. })): NoSolution
  --> src/lib.rs:14:25
   |
14 |     x.to_provider_ref().request::<Value<i32>>();
   |                         ^^^^^^^
   |
note: delayed at compiler/rustc_borrowck/src/type_check/mod.rs:1950:21 - disabled backtrace
  --> src/lib.rs:14:25
   |
14 |     x.to_provider_ref().request::<Value<i32>>();
   |                         ^^^^^^^

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: rustc 1.87.0 (17067e9ac 2025-05-09) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type lib -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

Backtrace

There are three errors so three backtraces.

  = note: delayed at compiler/rustc_trait_selection/src/traits/query/normalize.rs:287:30
             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>::delayed_bug::<alloc::string::String>
             4: <rustc_trait_selection::traits::query::normalize::QueryNormalizer as rustc_type_ir::fold::FallibleTypeFolder<rustc_middle::ty::context::TyCtxt>>::try_fold_ty
             5: <rustc_type_ir::ty_kind::FnSig<rustc_middle::ty::context::TyCtxt> as rustc_type_ir::fold::TypeFoldable<rustc_middle::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection::traits::query::normalize::QueryNormalizer>
             6: rustc_traits::type_op::type_op_normalize_fn_sig
             7: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::type_op_normalize_fn_sig::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
             8: <rustc_query_impl::query_impl::type_op_normalize_fn_sig::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_type_ir::canonical::CanonicalQueryInput<rustc_middle::ty::context::TyCtxt, rustc_middle::ty::ParamEnvAnd<rustc_middle::traits::query::type_op::Normalize<rustc_type_ir::ty_kind::FnSig<rustc_middle::ty::context::TyCtxt>>>>)>>::call_once
             9: <rustc_query_system::query::plumbing::execute_job_incr<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_type_ir::canonical::CanonicalQueryInput<rustc_middle::ty::context::TyCtxt, rustc_middle::ty::ParamEnvAnd<rustc_type_ir::ty_kind::AliasTy<rustc_middle::ty::context::TyCtxt>>>, rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt>::{closure#2}::{closure#2} as core::ops::function::FnOnce<((rustc_query_impl::plumbing::QueryCtxt, rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_type_ir::canonical::CanonicalQueryInput<rustc_middle::ty::context::TyCtxt, rustc_middle::ty::ParamEnvAnd<rustc_type_ir::ty_kind::AliasTy<rustc_middle::ty::context::TyCtxt>>>, rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>), rustc_type_ir::canonical::CanonicalQueryInput<rustc_middle::ty::context::TyCtxt, rustc_middle::ty::ParamEnvAnd<rustc_type_ir::ty_kind::AliasTy<rustc_middle::ty::context::TyCtxt>>>)>>::call_once
            10: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_type_ir::canonical::CanonicalQueryInput<rustc_middle::ty::context::TyCtxt, rustc_middle::ty::ParamEnvAnd<rustc_middle::traits::query::type_op::Normalize<rustc_type_ir::ty_kind::FnSig<rustc_middle::ty::context::TyCtxt>>>>, rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
            11: rustc_query_impl::query_impl::type_op_normalize_fn_sig::get_query_incr::__rust_end_short_backtrace
            12: <rustc_type_ir::ty_kind::FnSig<rustc_middle::ty::context::TyCtxt> as rustc_trait_selection::traits::query::type_op::normalize::Normalizable>::type_op_method
            13: <rustc_middle::ty::ParamEnvAnd<rustc_middle::traits::query::type_op::DeeplyNormalize<rustc_type_ir::ty_kind::FnSig<rustc_middle::ty::context::TyCtxt>>> as rustc_trait_selection::traits::query::type_op::TypeOp>::fully_perform
            14: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_body
            15: rustc_borrowck::type_check::type_check
            16: rustc_borrowck::nll::compute_regions
            17: rustc_borrowck::do_mir_borrowck
            18: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
            19: 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; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
            20: rustc_query_impl::query_impl::mir_borrowck::get_query_incr::__rust_end_short_backtrace
            21: rustc_interface::passes::run_required_analyses
            22: rustc_interface::passes::analysis
            23: 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]>>
            24: 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, true>
            25: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
            26: 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}
            27: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
            28: 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}, ()>
            29: <<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}
            30: std::sys::pal::unix::thread::Thread::new::thread_start
            31: <unknown>
            32: <unknown>

note: delayed at /rustc/17067e9ac6d7ecb70e50f92c1944e545188d2359/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:87:25
         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, alloc::string::String>
         4: <rustc_middle::ty::ParamEnvAnd<rustc_middle::traits::query::type_op::DeeplyNormalize<rustc_type_ir::ty_kind::FnSig<rustc_middle::ty::context::TyCtxt>>> as rustc_trait_selection::traits::query::type_op::TypeOp>::fully_perform
         5: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_body
         6: rustc_borrowck::type_check::type_check
         7: rustc_borrowck::nll::compute_regions
         8: rustc_borrowck::do_mir_borrowck
         9: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        10: 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; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
        11: rustc_query_impl::query_impl::mir_borrowck::get_query_incr::__rust_end_short_backtrace
        12: rustc_interface::passes::run_required_analyses
        13: rustc_interface::passes::analysis
        14: 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]>>
        15: 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, true>
        16: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
        17: 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}
        18: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        19: 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}, ()>
        20: <<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}
        21: std::sys::pal::unix::thread::Thread::new::thread_start
        22: <unknown>
        23: <unknown>

note: delayed at compiler/rustc_borrowck/src/type_check/mod.rs:1950:21
         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, alloc::string::String>
         4: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_body
         5: rustc_borrowck::type_check::type_check
         6: rustc_borrowck::nll::compute_regions
         7: rustc_borrowck::do_mir_borrowck
         8: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
         9: 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; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
        10: rustc_query_impl::query_impl::mir_borrowck::get_query_incr::__rust_end_short_backtrace
        11: rustc_interface::passes::run_required_analyses
        12: rustc_interface::passes::analysis
        13: 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]>>
        14: 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, true>
        15: rustc_query_impl::query_impl::analysis::get_query_incr::__rust_end_short_backtrace
        16: 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}
        17: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        18: 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}, ()>
        19: <<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}
        20: std::sys::pal::unix::thread::Thread::new::thread_start
        21: <unknown>
        22: <unknown>

[konnorandrews]

-Znext-solver=globally does work without an ICE but takes about 20s-30s to check the code.

[konnorandrews]

Its possible this is a form of #105299 but the reproducer listed in that issue no longer causes an ICE and this generates a different error message in the ICE.

[theemathas]

Slightly smaller reproducer, but still huge: supply.zip

[theemathas]

Single-file reproducer (195 lines):

Code:

use core::marker::PhantomData;

// pub fn pretty_print<T: for<'r> ToProviderRef<'r>>(x: &T) { // works (normal error)
pub fn pretty_print<'r, T: ToProviderRef<'r>>() {
    request::<<T as ToProviderRef<'_>>::ProviderRef, Value<i32>>();
}

fn request<'arg, T: LifetimeList, R: RequestWithArg<Lt<'arg, T>>>() -> R::Output {
    unimplemented!()
}

trait RequestWithArg<L> {
    type Output;
}

impl<L, T> RequestWithArg<L> for T
where
    L: LifetimeList,
    T: GiveMeta<L>,
{
    type Output = ();
}

pub trait ToProviderRef<'r> {
    type ProviderRef: LifetimeList;
}

struct Infer();

struct Value<Tag: ?Sized = Infer, Pat: ?Sized = Infer>(PhantomData<Tag>, PhantomData<Pat>);

impl<L, Tag, Pat> GiveMeta<L> for Value<Tag, Pat>
where
    L: LifetimeList,
    Pat: ProjectionFor<L>,
{
}

impl<Tag, L> GiveMeta<L> for Value<Tag, Infer> {}

trait GiveMeta<Lifetimes> {}

struct WantForTag<Value: ?Sized, ValueLen: ?Sized>(
    PhantomData<fn() -> (*const Value, *const ValueLen)>,
);

impl<Value: Tag, ValueLen: Num> Tag for WantForTag<Value, ValueLen> {}

impl<Value: ?Sized + Tagged, ValueLen> TagFor for WantForTag<Value, ValueLen>
where
    ValueLen: Num,
{
    type Tag = WantForTag<<Value as Tagged>::Tag, ValueLen>;
}

pub trait Tag: Sized + Tagged<Tag = Self> + Send + Sync + Unpin {}

pub trait Tagged {
    type Tag;
}

pub type TagOf<T> = <T as Tagged>::Tag;

pub trait TagFor {
    type Tag;
}

impl<T: ?Sized> Tagged for T
where
    T: TagFor,
{
    type Tag = <T as TagFor>::Tag;
}

pub trait Reifies<L>: Tag {
    type Reified: ?Sized;
}

pub type ReifiedOf<T, L> = <<T as Tagged>::Tag as Reifies<L>>::Reified;

pub trait ReifiableWith<Lifetimes: LifetimeList>:
    Tagged<Tag: Reifies<Lifetimes, Reified = Self::Reified>>
{
    type Reified: ?Sized;
}

impl<T, Lifetimes> ReifiableWith<Lifetimes> for T
where
    Lifetimes: LifetimeList,
    T: ?Sized + Tagged<Tag: Reifies<Lifetimes>>,
{
    type Reified = ReifiedOf<T, Lifetimes>;
}

pub struct I32;
impl Tag for I32 {}
impl TagFor for i32 {
    type Tag = I32;
}
impl TagFor for I32 {
    type Tag = I32;
}
impl<T> Reifies<T> for I32 {
    type Reified = i32;
}

pub struct NZero;
pub struct NOne<N>(PhantomData<fn() -> N>);
pub trait Num: Sized {}
impl Num for NZero {}
impl<T: Num> Num for NOne<T> {}

#[allow(clippy::type_complexity)]
pub struct Lt<'lt, Tail = Nil>(PhantomData<fn(&'lt ()) -> (&'lt (), Tail)>);

pub struct Nil;

pub trait LifetimeList: LifetimeListType + LifetimeListOps {}

impl<L: LifetimeListOps> LifetimeList for L {}

pub trait LifetimeListType: Sized + Send + Sync + Unpin {
    type Len: Num;
}

pub trait SplitAt: LifetimeListType<Len: Num> {}
impl SplitAt for Nil {}
impl<'lt, Tail: LifetimeList> SplitAt for Lt<'lt, Tail> {}

pub trait LifetimeListOps:
    LifetimeListType + Tagged<Tag = LifetimeListTag<LenOf<Self>>> + SplitAt
{
}

impl<L> LifetimeListOps for L where
    L: LifetimeListType + Tagged<Tag = LifetimeListTag<LenOf<Self>>> + SplitAt
{
}

pub trait ProjectionFor<Lifetimes: LifetimeList>:
    Projection<Projector: Projector + Transforms<Lifetimes, Output = Self::Output>>
{
    type Output: LifetimeList;

    type Len: Num;
}

impl<P, Lifetimes> ProjectionFor<Lifetimes> for P
where
    Lifetimes: LifetimeList,
    P: Projection,
    P::Projector: Transforms<Lifetimes>,
{
    type Output = <P::Projector as Transforms<Lifetimes>>::Output;

    type Len = <P::Projector as Projector>::Len;
}

pub trait Projector: Sized + 'static {
    type Len: Num;
}

pub trait Transforms<L: LifetimeListType>: Projector {
    type Output: LifetimeList;
}

pub trait Projection {
    type Projector;
}
pub type LenOf<L> = <L as LifetimeListType>::Len;

impl LifetimeListType for Nil {
    type Len = NZero;
}

impl<Tail: LifetimeListType> LifetimeListType for Lt<'_, Tail> {
    type Len = NOne<Tail::Len>;
}

pub struct LifetimeListTag<N>(PhantomData<fn() -> N>);

impl<N> Tag for LifetimeListTag<N> {}

impl<Tail, U> TagFor for Lt<'_, Tail>
where
    U: Num,
    Tail: LifetimeListType + Tagged<Tag = LifetimeListTag<U>>,
{
    type Tag = LifetimeListTag<NOne<U>>;
}

impl<N> TagFor for LifetimeListTag<N> {
    type Tag = LifetimeListTag<N>;
}

[theemathas]

98-line reproducer:

Code:

use core::marker::PhantomData;

// pub fn pretty_print<T: for<'r> ToProviderRef<'r>>(x: &T) { // works (normal error)
pub fn pretty_print<'r, T: ToProviderRef<'r>>() {
    request::<<T as ToProviderRef<'_>>::ProviderRef, Value<i32>>();
}

fn request<T: Peano, R: RequestWithArg<PeanoSucc<T>>>() -> R::Output {
    unimplemented!()
}

trait RequestWithArg<P> {
    type Output;
}

impl<P, T> RequestWithArg<P> for T
where
    P: Peano,
    T: GiveMeta<P>,
{
    type Output = ();
}

pub trait ToProviderRef<'r> {
    type ProviderRef: Peano;
}

struct Infer;

struct Value<Tag: ?Sized = Infer, Pat: ?Sized = Infer>(PhantomData<Tag>, PhantomData<Pat>);

impl<P, Tag, Pat> GiveMeta<P> for Value<Tag, Pat>
where
    P: Peano,
    Pat: std::fmt::Debug, // The Debug bound is to avoid overlapping impls
{
}

impl<Tag, P> GiveMeta<P> for Value<Tag, Infer> {}

trait GiveMeta<Lifetimes> {}

pub trait Tagged {
    type Tag;
}

pub trait Unimplemented {}
impl<T: Unimplemented> Tagged for T {
    type Tag = ();
}

pub trait Reifies<P> {
    type Reified: ?Sized;
}

pub trait ReifiableWith<P: Peano>: Tagged<Tag: Reifies<P, Reified = Self::Reified>> {
    type Reified: ?Sized;
}

impl<T, P> ReifiableWith<P> for T
where
    P: Peano,
    T: ?Sized + Tagged<Tag: Reifies<P>>,
{
    type Reified = <<T as Tagged>::Tag as Reifies<P>>::Reified;
}

pub struct PeanoZero;
pub struct PeanoSucc<N>(PhantomData<N>);

pub trait Peano: Tagged<Tag = LifetimeListTag<LenOf<Self>>> + SplitAt {}
impl<P: Tagged<Tag = LifetimeListTag<LenOf<P>>> + SplitAt> Peano for P {}

pub trait SplitAt: PeanoType<Len: Sized> {}
impl SplitAt for PeanoZero {}
impl<P: Peano> SplitAt for PeanoSucc<P> {}

pub struct Dummy;

pub trait PeanoType {
    type Len;
}
impl PeanoType for PeanoZero {
    type Len = Dummy;
}
impl<P: PeanoType> PeanoType for PeanoSucc<P> {
    type Len = Dummy;
}
pub type LenOf<P> = <P as PeanoType>::Len;

pub struct LifetimeListTag<N>(PhantomData<fn() -> N>);
impl<P, U> Tagged for PeanoSucc<P>
where
    P: Tagged<Tag = LifetimeListTag<U>>,
{
    type Tag = LifetimeListTag<Dummy>;
}

[matthiaskrgr]

auto-reduced a bit futher 🤷

fn pretty_print<'r, T: ToProviderRef<'r>>() {
    request::<T::ProviderRef, Value>()
}
fn request<T, R: RequestWithArg<PeanoSucc<T>>>() -> R::Output {
    unimplemented!()
}
trait RequestWithArg<P> {
    type Output;
}
impl<P, T> RequestWithArg<P> for T
where
    P: Peano,
{
    type Output = ();
}
trait ToProviderRef<'r> {
    type ProviderRef: Peano;
}
struct Value;
trait Tagged {
    type Tag;
}
trait Unimplemented {}
impl<T: Unimplemented> Tagged for T {
    type Tag = ();
}
struct PeanoSucc<N>(N);
trait Peano: Tagged<Tag = LifetimeListTag<LenOf<Self>>> + SplitAt {}
impl<P: Tagged<Tag = LifetimeListTag<LenOf<P>>>> Peano for P {}
trait SplitAt: PeanoType<Len: Sized> {}
impl<P> SplitAt for P {}
struct Dummy;
trait PeanoType {
    type Len;
}
impl<P> PeanoType for P {
    type Len = Dummy;
}
type LenOf<P> = <P as PeanoType>::Len;
struct LifetimeListTag<N>(N);
impl<P, U> Tagged for PeanoSucc<P>
where
    P: Tagged<Tag = LifetimeListTag<U>>,
{
    type Tag = LifetimeListTag<Dummy>;
}

[moxian]

Bisection points to nightly-2024-02-11. PRs in range:

 - #120852 (Rollup of 11 pull requests) by matthiaskrgr
   - #120351 (Implement SystemTime for UEFI)
   - #120354 (improve normalization of `Pointee::Metadata`)
   - #120776 (Move path implementations into `sys`)
   - #120790 (better error message on download CI LLVM failure)
   - #120806 (Clippy subtree update)
   - #120815 (Improve `Option::inspect` docs)
   - #120822 (Emit more specific diagnostics when enums fail to cast with `as`)
   - #120827 (Print image input file and checksum in CI only)
   - #120836 (hide impls if trait bound is proven from env)
   - #120844 (Build DebugInfo for async closures)
   - #120851 (Remove duplicate release note)
 - #120862 (Rollup of 6 pull requests) by matthiaskrgr
   - #120584 (For a rigid projection, recursively look at the self type's item bounds to fix the `associated_type_bounds` feature)
   - #120596 ([rustdoc] Correctly generate path for non-local items in source code pages)
   - #120629 (Move some test files)
   - #120846 (Update jobserver-rs to 0.1.28)
   - #120850 (ast_lowering: Fix regression in `use ::{}` imports.)
   - #120853 (Avoid a collection and iteration on empty passes)
 - #120721 (fix `llvm_out` to use the correct LLVM root) by onur-ozkan
 - #120712 (Harmonize `AsyncFn` implementations, make async closures conditionally impl `Fn*` traits) by compiler-errors
 - #120771 (Use `ensure` when the result of the query is not needed beyond its `Result`ness) by oli-obk
 - #120877 (Rollup of 8 pull requests) by matthiaskrgr
   - #117614 (static mut: allow mutable reference to arbitrary types, not just slices and arrays)
   - #120719 (Remove support for `associated_type_bound` nested in `dyn` types)
   - #120764 (Add documentation on `str::starts_with`)
   - #120823 (Clarify that atomic and regular integers can differ in alignment)
   - #120859 (Loosen an assertion to account for stashed errors.)
   - #120865 (Turn the "no saved object file in work product" ICE into a translatable fatal error)
   - #120866 (Remove unnecessary `#![feature(min_specialization)]`)
   - #120870 (Allow restricted trait impls under `#[allow_internal_unstable(min_specialization)]`)
 - #119614 (unstably allow constants to refer to statics and read from immutable statics) by RalfJung

Sounds like one of the two associated_type_bounds PRs (#120584 or, perhaps less likely, #120719)

[cyrgani]

simpler:

fn pretty_print<'r, T: ToProviderRef<'r>>() {
    request::<T::ProviderRef, u8>()
}
fn request<T, R: RequestWithArg<PeanoSucc<T>>>() -> R::Output {
    unimplemented!()
}
trait RequestWithArg<P> {
    type Output;
}
impl<P, T> RequestWithArg<P> for T
where
    P: Tagged,
{
    type Output = ();
}
trait ToProviderRef<'r> {
    type ProviderRef: Tagged<Tag: Sized>;
}
trait Tagged {
    type Tag;
}
trait Unimplemented {}
impl<T: Unimplemented> Tagged for T {
    type Tag = ();
}
struct PeanoSucc<N>(N);
impl<P, U> Tagged for PeanoSucc<P>
where
    P: Tagged<Tag = U>,
{
    type Tag = ();
}