incremental compilation error when using higher-ranked-assumptions #16181
Description
Summary
The bug has probably something to do with a function in my website rewrite that requires higher-ranked-assumptions. I don't understand that rust feature well enough to create a minimal example but my codebase is relatively small.
It does not happen when using cargo check, only with cargo clippy. (Same flags.)
Version
rustc 1.93.0-nightly (1d60f9e07 2025-12-01)
binary: rustc
commit-hash: 1d60f9e070c1039b263e0f035c0f03dfcc610d0f
commit-date: 2025-12-01
host: x86_64-unknown-linux-gnu
release: 1.93.0-nightly
LLVM version: 21.1.5
Error output
Backtrace
Checking server v0.1.0 (/var/home/jak2k/Projects/website/server)
error: internal compiler error: encountered incremental compilation error with evaluate_obligation(d303707cd49c89e8-bedf91044e5103ea)
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= note: please follow the instructions below to create a bug report with the provided information
= note: for incremental compilation bugs, having a reproduction is vital
= note: an ideal reproduction consists of the code before and some patch that then triggers the bug when applied and compiled again
= note: as a workaround, you can run `cargo clean -p server` or `cargo clean` to allow your project to compile
thread 'rustc' (104485) panicked at /rustc-dev/1d60f9e070c1039b263e0f035c0f03dfcc610d0f/compiler/rustc_query_system/src/query/plumbing.rs:752:9:
Found unstable fingerprints for evaluate_obligation(d303707cd49c89e8-bedf91044e5103ea): Ok(EvaluatedToOk)
stack backtrace:
0: __rustc::rust_begin_unwind
1: core::panicking::panic_fmt
2: rustc_query_system::query::plumbing::incremental_verify_ich_failed::<rustc_middle::ty::context::TyCtxt>
3: 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::ty::predicate::Predicate>>, rustc_middle::query::erase::Erased<[u8; 2]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, true>
4: <rustc_trait_selection::traits::fulfill::FulfillProcessor as rustc_data_structures::obligation_forest::ObligationProcessor>::process_obligation
5: <rustc_data_structures::obligation_forest::ObligationForest<rustc_trait_selection::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection::traits::fulfill::FulfillProcessor>
6: <rustc_trait_selection::traits::engine::ObligationCtxt>::make_canonicalized_query_response::<()>
7: rustc_traits::type_op::type_op_prove_predicate
[... omitted 2 frames ...]
8: <rustc_borrowck::type_check::TypeChecker>::normalize_and_prove_instantiated_predicates
9: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_operand
10: <rustc_borrowck::type_check::TypeChecker as rustc_middle::mir::visit::Visitor>::visit_body
11: rustc_borrowck::type_check::type_check
12: <rustc_borrowck::root_cx::BorrowCheckRootCtxt>::do_mir_borrowck
13: rustc_borrowck::mir_borrowck
[... omitted 1 frame ...]
14: rustc_hir_analysis::collect::type_of::opaque::find_opaque_ty_constraints_for_rpit
15: rustc_hir_analysis::collect::type_of::type_of_opaque
[... omitted 1 frame ...]
16: <rustc_trait_selection::traits::select::SelectionContext>::confirm_auto_impl_candidate::{closure#0}
17: <rustc_trait_selection::traits::select::SelectionContext>::confirm_candidate
18: <rustc_trait_selection::traits::select::SelectionContext>::evaluate_trait_predicate_recursively
19: <rustc_trait_selection::traits::select::SelectionContext>::evaluate_predicate_recursively
20: <rustc_trait_selection::traits::select::SelectionContext>::evaluate_trait_predicate_recursively
21: <rustc_trait_selection::traits::select::SelectionContext>::evaluate_root_obligation
22: rustc_traits::evaluate_obligation::evaluate_obligation
[... omitted 2 frames ...]
23: <rustc_trait_selection::traits::fulfill::FulfillProcessor as rustc_data_structures::obligation_forest::ObligationProcessor>::process_obligation
24: <rustc_data_structures::obligation_forest::ObligationForest<rustc_trait_selection::traits::fulfill::PendingPredicateObligation>>::process_obligations::<rustc_trait_selection::traits::fulfill::FulfillProcessor>
25: <rustc_trait_selection::traits::fulfill::FulfillmentContext<rustc_trait_selection::traits::FulfillmentError> as rustc_infer::traits::engine::TraitEngine<rustc_trait_selection::traits::FulfillmentError>>::evaluate_obligations_error_on_ambiguity
26: <rustc_trait_selection::traits::engine::ObligationCtxt<rustc_trait_selection::traits::FulfillmentError>>::evaluate_obligations_error_on_ambiguity
27: <clippy_lints::future_not_send::FutureNotSend as rustc_lint::passes::LateLintPass>::check_fn
28: <rustc_lint::late::LateContextAndPass<rustc_lint::late::RuntimeCombinedLateLintPass> as rustc_hir::intravisit::Visitor>::visit_fn
29: <rustc_lint::late::LateContextAndPass<rustc_lint::late::RuntimeCombinedLateLintPass> as rustc_hir::intravisit::Visitor>::visit_nested_item
30: <rustc_lint::late::LateContextAndPass<rustc_lint::late::RuntimeCombinedLateLintPass>>::process_mod
31: <rustc_lint::late::LateContextAndPass<rustc_lint::late::RuntimeCombinedLateLintPass> as rustc_hir::intravisit::Visitor>::visit_nested_item
32: <rustc_lint::late::LateContextAndPass<rustc_lint::late::RuntimeCombinedLateLintPass>>::process_mod
33: rustc_lint::late::check_crate::{closure#0}
34: rustc_lint::late::check_crate
35: rustc_interface::passes::analysis
[... omitted 1 frame ...]
36: <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} as core::ops::function::FnOnce<(&rustc_session::session::Session, rustc_middle::ty::context::CurrentGcx, alloc::sync::Arc<rustc_data_structures::jobserver::Proxy>, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
37: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
error: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new?template=ice.yml
note: please make sure that you have updated to the latest nightly
note: please attach the file at `/var/home/jak2k/Projects/website/server/rustc-ice-2025-12-02T20_38_52-104484.txt` to your bug report
note: compiler flags: --crate-type bin -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED] -Z higher-ranked-assumptions
note: some of the compiler flags provided by cargo are hidden
query stack during panic:
#0 [evaluate_obligation] evaluating trait selection obligation `core::iter::adapters::map::Map<std::collections::hash::map::IntoIter<std::path::PathBuf, alloc::string::String>, {async closure@src/deploy.rs:66:43: 66:70}>: core::iter::traits::collect::IntoIterator`
#1 [type_op_prove_predicate] evaluating `type_op_prove_predicate` `ProvePredicate { predicate: Binder { value: TraitPredicate(<core::iter::adapters::map::Map<std::collections::hash::map::IntoIter<std::path::PathBuf, alloc::string::String>, {async closure@src/deploy.rs:66:43: 66:70}> as core::iter::traits::collect::IntoIterator>, polarity:Positive), bound_vars: [] } }`
#2 [mir_borrowck] borrow-checking `deploy::build`
#3 [type_of_opaque] computing type of opaque `deploy::build::{opaque#0}`
#4 [evaluate_obligation] evaluating trait selection obligation `{coroutine witness@src/deploy.rs:17:89: 46:2}: core::marker::Send`
#5 [analysis] running analysis passes on crate `server`
end of query stack
note: Clippy version: clippy 0.1.93 (1d60f9e070 2025-12-01)
error: could not compile `server` (bin "server") due to 1 previous error