Cycle error happens when using inherent_associated_types and generic_const_exprs features #136678
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Code
#![feature(inherent_associated_types)] #![feature(generic_const_exprs)] #![allow(incomplete_features)] struct B<const A: usize>; struct Test<const A: usize>; impl<const A: usize> Test<A> { type B = B<{ A }>; fn test(a: Self::B) -> Self::B { a } }Meta
rustc --version --verbose:
rustc 1.86.0-nightly (942db6782 2025-02-06) binary: rustc commit-hash: 942db6782f4a28c55b0b75b38fd4394d0483390f commit-date: 2025-02-06 host: aarch64-apple-darwin release: 1.86.0-nightly LLVM version: 19.1.7 Error output
error: internal compiler error[E0391]: cycle detected when computing function signature of `<impl at src/lib.rs:9:1: 9:29>::test` --> src/lib.rs:12:5 | 12 | fn test(a: Self::B) -> Self::B { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | note: ...which requires computing normalized predicates of `<impl at src/lib.rs:9:1: 9:29>::test`... --> src/lib.rs:12:5 | 12 | fn test(a: Self::B) -> Self::B { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires computing predicates of `<impl at src/lib.rs:9:1: 9:29>::test`... --> src/lib.rs:12:5 | 12 | fn test(a: Self::B) -> Self::B { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires computing explicit predicates of `<impl at src/lib.rs:9:1: 9:29>::test`... --> src/lib.rs:12:5 | 12 | fn test(a: Self::B) -> Self::B { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: ...which again requires computing function signature of `<impl at src/lib.rs:9:1: 9:29>::test`, completing the cycle = note: cycle used when computing the variances for items in this crate = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information note: delayed at compiler/rustc_query_system/src/query/job.rs:563:16 - disabled backtrace --> src/lib.rs:12:5 | 12 | fn test(a: Self::B) -> Self::B { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Backtrace
note: delayed at compiler/rustc_query_system/src/query/job.rs:563:16 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::diagnostic::Diag>::delay_as_bug 4: rustc_query_system::query::plumbing::mk_cycle::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::consts::valtree::Value, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt> 5: rustc_query_system::query::plumbing::cycle_error::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefaultCache<rustc_middle::ty::consts::valtree::Value, rustc_middle::query::erase::Erased<[u8; 24]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt> 6: 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> 7: rustc_query_impl::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace 8: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>> 9: rustc_hir_analysis::collect::predicates_of::gather_explicit_predicates_of 10: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::explicit_predicates_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>> 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::explicit_predicates_of::get_query_non_incr::__rust_end_short_backtrace 13: rustc_hir_analysis::collect::predicates_of::predicates_of 14: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::predicates_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 24]>> 15: 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> 16: rustc_query_impl::query_impl::predicates_of::get_query_non_incr::__rust_end_short_backtrace 17: rustc_ty_utils::ty::param_env 18: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::param_env::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_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 20: rustc_query_impl::query_impl::param_env::get_query_non_incr::__rust_end_short_backtrace 21: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 8]>>> 22: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_assoc_path 23: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_ty 24: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_fn_ty 25: rustc_hir_analysis::collect::lower_fn_sig_recovering_infer_ret_ty 26: rustc_hir_analysis::collect::fn_sig 27: 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]>> 28: <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 29: 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> 30: rustc_query_impl::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace 31: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 24]>>> 32: <rustc_hir_analysis::variance::constraints::ConstraintContext>::build_constraints_for_item 33: rustc_hir_analysis::variance::crate_variances 34: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::crate_variances::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>> 35: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 8]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 36: rustc_query_impl::query_impl::crate_variances::get_query_non_incr::__rust_end_short_backtrace 37: rustc_hir_analysis::variance::variances_of 38: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::variances_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 16]>> 39: <rustc_query_impl::query_impl::variances_of::dynamic_query::{closure#2} as core::ops::function::FnOnce<(rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId)>>::call_once 40: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 16]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false> 41: rustc_query_impl::query_impl::variances_of::get_query_non_incr::__rust_end_short_backtrace 42: rustc_middle::query::plumbing::query_get_at::<rustc_query_system::query::caches::DefIdCache<rustc_middle::query::erase::Erased<[u8; 16]>>> 43: rustc_hir_analysis::check::wfcheck::check_variances_for_type_defn 44: rustc_hir_analysis::check::wfcheck::check_well_formed 45: 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]>> 46: 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> 47: rustc_query_impl::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace 48: rustc_hir_analysis::check::wfcheck::check_mod_type_wf 49: 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]>> 50: 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> 51: rustc_query_impl::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace 52: rustc_hir_analysis::check_crate 53: rustc_interface::passes::run_required_analyses 54: rustc_interface::passes::analysis 55: 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]>> 56: 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> 57: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace 58: 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} 59: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1} 60: 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}, ()> 61: <<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} 62: std::sys::pal::unix::thread::Thread::new::thread_start 63: <unknown> 64: clone --> src/lib.rs:12:5 | 12 | fn test(a: Self::B) -> Self::B { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Metadata
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Category: This is a bug.`#![feature(generic_const_exprs)]``#![feature(inherent_associated_types)]`Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️Issue: A query cycle occurred while none was expectedStatus: This bug is tracked inside the repo by a `known-bug` test.Relevant to the compiler team, which will review and decide on the PR/issue.This issue requires the use of incomplete features.