warning: the feature `never_patterns` is incomplete and may not be safe to use and/or cause compiler crashes
--> code.rs:2:12
|
2 | #![feature(never_patterns)]
| ^^^^^^^^^^^^^^
|
= note: see issue #118155 <https://github.com/rust-lang/rust/issues/118155> for more information
= note: `#[warn(incomplete_features)]` on by default
thread 'rustc' (1168854) panicked at /rustc-dev/d933cf483edf1605142ac6899ff32536c0ad8b22/compiler/rustc_type_ir/src/ty_kind.rs:787:60:
called `Option::unwrap()` on a `None` value
stack backtrace:
0: 0x7f46efd5ef7b - <<std[69d51b4813ba037]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[51d4adbef590f61]::fmt::Display>::fmt
1: 0x7f46f04229c8 - core[51d4adbef590f61]::fmt::write
2: 0x7f46efd75f86 - <std[69d51b4813ba037]::sys::stdio::unix::Stderr as std[69d51b4813ba037]::io::Write>::write_fmt
3: 0x7f46efd35058 - std[69d51b4813ba037]::panicking::default_hook::{closure#0}
4: 0x7f46efd523e3 - std[69d51b4813ba037]::panicking::default_hook
5: 0x7f46eed3d71c - std[69d51b4813ba037]::panicking::update_hook::<alloc[18203fec9a0cd4ec]::boxed::Box<rustc_driver_impl[9032f3c5cdcc149c]::install_ice_hook::{closure#1}>>::{closure#0}
6: 0x7f46efd526c2 - std[69d51b4813ba037]::panicking::panic_with_hook
7: 0x7f46efd3514a - std[69d51b4813ba037]::panicking::panic_handler::{closure#0}
8: 0x7f46efd2be49 - std[69d51b4813ba037]::sys::backtrace::__rust_end_short_backtrace::<std[69d51b4813ba037]::panicking::panic_handler::{closure#0}, !>
9: 0x7f46efd36b7d - __rustc[cb16bc19fc993bd7]::rust_begin_unwind
10: 0x7f46ec91895c - core[51d4adbef590f61]::panicking::panic_fmt
11: 0x7f46ec3fea02 - core[51d4adbef590f61]::panicking::panic
12: 0x7f46ecfefc69 - core[51d4adbef590f61]::option::unwrap_failed
13: 0x7f46f0d2d4b3 - rustc_trait_selection[a0d03008c221415d]::traits::dyn_compatibility::virtual_call_violations_for_method
14: 0x7f46f160bc22 - rustc_trait_selection[a0d03008c221415d]::traits::dyn_compatibility::dyn_compatibility_violations_for_assoc_item
15: 0x7f46f160b6d8 - <core[51d4adbef590f61]::iter::adapters::flatten::FlatMap<core[51d4adbef590f61]::iter::adapters::map::Map<core[51d4adbef590f61]::iter::adapters::map::Map<core[51d4adbef590f61]::slice::iter::Iter<(core[51d4adbef590f61]::option::Option<rustc_span[a0277d8dc90b615]::symbol::Symbol>, rustc_middle[7e63d2df2dd45427]::ty::assoc::AssocItem)>, <rustc_data_structures[889238d3fa4068cd]::sorted_map::index_map::SortedIndexMultiMap<u32, core[51d4adbef590f61]::option::Option<rustc_span[a0277d8dc90b615]::symbol::Symbol>, rustc_middle[7e63d2df2dd45427]::ty::assoc::AssocItem>>::iter::{closure#0}>, <rustc_middle[7e63d2df2dd45427]::ty::assoc::AssocItems>::in_definition_order::{closure#0}>, alloc[18203fec9a0cd4ec]::vec::Vec<rustc_middle[7e63d2df2dd45427]::traits::DynCompatibilityViolation>, rustc_trait_selection[a0d03008c221415d]::traits::dyn_compatibility::dyn_compatibility_violations_for_trait::{closure#0}::{closure#0}> as core[51d4adbef590f61]::iter::traits::iterator::Iterator>::next
16: 0x7f46f16096e9 - <core[51d4adbef590f61]::iter::adapters::GenericShunt<core[51d4adbef590f61]::iter::adapters::map::Map<core[51d4adbef590f61]::iter::adapters::flatten::FlatMap<core[51d4adbef590f61]::iter::sources::from_fn::FromFn<rustc_type_ir[505b55bac6a24d17]::elaborate::supertrait_def_ids<rustc_middle[7e63d2df2dd45427]::ty::context::TyCtxt>::{closure#0}>, alloc[18203fec9a0cd4ec]::vec::Vec<rustc_middle[7e63d2df2dd45427]::traits::DynCompatibilityViolation>, rustc_trait_selection[a0d03008c221415d]::traits::dyn_compatibility::dyn_compatibility_violations::{closure#0}>, core[51d4adbef590f61]::result::Result<rustc_middle[7e63d2df2dd45427]::traits::DynCompatibilityViolation, !>::Ok>, core[51d4adbef590f61]::result::Result<core[51d4adbef590f61]::convert::Infallible, !>> as core[51d4adbef590f61]::iter::traits::iterator::Iterator>::next
17: 0x7f46f1608abc - rustc_trait_selection[a0d03008c221415d]::traits::dyn_compatibility::dyn_compatibility_violations
18: 0x7f46f16089ac - rustc_query_impl[540cdfee4f8a4756]::query_impl::dyn_compatibility_violations::invoke_provider_fn::__rust_begin_short_backtrace
19: 0x7f46f06ecfb7 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_middle[7e63d2df2dd45427]::query::caches::DefIdCache<rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 16usize]>>, false>
20: 0x7f46f0ddec27 - rustc_query_impl[540cdfee4f8a4756]::query_impl::dyn_compatibility_violations::execute_query_non_incr::__rust_end_short_backtrace
21: 0x7f46f0ddecc0 - rustc_trait_selection[a0d03008c221415d]::traits::dyn_compatibility::is_dyn_compatible
22: 0x7f46f0ddec57 - rustc_query_impl[540cdfee4f8a4756]::query_impl::is_dyn_compatible::invoke_provider_fn::__rust_begin_short_backtrace
23: 0x7f46f0dd854a - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_middle[7e63d2df2dd45427]::query::caches::DefIdCache<rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 1usize]>>, false>
24: 0x7f46f0dd6fc0 - rustc_query_impl[540cdfee4f8a4756]::query_impl::is_dyn_compatible::execute_query_non_incr::__rust_end_short_backtrace
25: 0x7f46f17e64be - <dyn rustc_hir_analysis[bceba1a8102fadd5]::hir_ty_lowering::HirTyLowerer>::prohibit_or_lint_bare_trait_object_ty
26: 0x7f46f12476ff - <dyn rustc_hir_analysis[bceba1a8102fadd5]::hir_ty_lowering::HirTyLowerer>::lower_trait_object_ty
27: 0x7f46f0ab45bc - <dyn rustc_hir_analysis[bceba1a8102fadd5]::hir_ty_lowering::HirTyLowerer>::lower_ty
28: 0x7f46f0acaeaf - <dyn rustc_hir_analysis[bceba1a8102fadd5]::hir_ty_lowering::HirTyLowerer>::lower_fn_ty
29: 0x7f46f06f14bc - rustc_hir_analysis[bceba1a8102fadd5]::collect::fn_sig
30: 0x7f46f06f0c26 - rustc_query_impl[540cdfee4f8a4756]::query_impl::fn_sig::invoke_provider_fn::__rust_begin_short_backtrace
31: 0x7f46f06f5360 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_middle[7e63d2df2dd45427]::query::caches::DefIdCache<rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 24usize]>>, false>
32: 0x7f46f06f4853 - rustc_query_impl[540cdfee4f8a4756]::query_impl::fn_sig::execute_query_non_incr::__rust_end_short_backtrace
33: 0x7f46f0adf473 - rustc_hir_analysis[bceba1a8102fadd5]::check::check::check_item_type
34: 0x7f46f0addca6 - rustc_hir_analysis[bceba1a8102fadd5]::check::wfcheck::check_well_formed
35: 0x7f46f0addc87 - rustc_query_impl[540cdfee4f8a4756]::query_impl::check_well_formed::invoke_provider_fn::__rust_begin_short_backtrace
36: 0x7f46f0add219 - rustc_query_impl[540cdfee4f8a4756]::execution::try_execute_query::<rustc_data_structures[889238d3fa4068cd]::vec_cache::VecCache<rustc_span[a0277d8dc90b615]::def_id::LocalDefId, rustc_middle[7e63d2df2dd45427]::query::erase::ErasedData<[u8; 1usize]>, rustc_middle[7e63d2df2dd45427]::dep_graph::graph::DepNodeIndex>, false>
37: 0x7f46f0adcf7b - rustc_query_impl[540cdfee4f8a4756]::query_impl::check_well_formed::execute_query_non_incr::__rust_end_short_backtrace
38: 0x7f46eeea25ca - <rustc_middle[7e63d2df2dd45427]::hir::ModuleItems>::par_opaques::<rustc_hir_analysis[bceba1a8102fadd5]::check::wfcheck::check_type_wf::{closure#5}>::{closure#0}
39: 0x7f46eef34c1b - <rustc_thread_pool[ad99c7f29618ca7]::job::HeapJob<<rustc_thread_pool[ad99c7f29618ca7]::scope::Scope>::spawn<rustc_data_structures[889238d3fa4068cd]::sync::parallel::par_slice<&rustc_span[a0277d8dc90b615]::def_id::LocalDefId, rustc_data_structures[889238d3fa4068cd]::sync::parallel::try_par_for_each_in<&[rustc_span[a0277d8dc90b615]::def_id::LocalDefId], rustc_span[a0277d8dc90b615]::ErrorGuaranteed, <rustc_middle[7e63d2df2dd45427]::hir::ModuleItems>::par_opaques<rustc_hir_analysis[bceba1a8102fadd5]::check::wfcheck::check_type_wf::{closure#5}>::{closure#0}>::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>::{closure#0}> as rustc_thread_pool[ad99c7f29618ca7]::job::Job>::execute
40: 0x7f46efa53c9f - <rustc_thread_pool[ad99c7f29618ca7]::registry::WorkerThread>::wait_or_steal_until_cold
41: 0x7f46efa52832 - <rustc_thread_pool[ad99c7f29618ca7]::registry::ThreadBuilder>::run
42: 0x7f46eed361dc - std[69d51b4813ba037]::sys::backtrace::__rust_begin_short_backtrace::<<rustc_thread_pool[ad99c7f29618ca7]::ThreadPoolBuilder>::build_scoped<rustc_interface[5b554394f8ce662a]::util::run_in_thread_pool_with_globals<rustc_interface[5b554394f8ce662a]::interface::run_compiler<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface[5b554394f8ce662a]::util::run_in_thread_pool_with_globals<rustc_interface[5b554394f8ce662a]::interface::run_compiler<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
43: 0x7f46eed402e3 - <std[69d51b4813ba037]::thread::lifecycle::spawn_unchecked<<rustc_thread_pool[ad99c7f29618ca7]::ThreadPoolBuilder>::build_scoped<rustc_interface[5b554394f8ce662a]::util::run_in_thread_pool_with_globals<rustc_interface[5b554394f8ce662a]::interface::run_compiler<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface[5b554394f8ce662a]::util::run_in_thread_pool_with_globals<rustc_interface[5b554394f8ce662a]::interface::run_compiler<(), rustc_driver_impl[9032f3c5cdcc149c]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>::{closure#1} as core[51d4adbef590f61]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
44: 0x7f46f165dbec - <std[69d51b4813ba037]::sys::thread::unix::Thread>::new::thread_start
45: 0x7f46eb05e98b - <unknown>
46: 0x7f46eb0e2a0c - <unknown>
47: 0x0 - <unknown>
error: the compiler unexpectedly panicked. This is a bug
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 `/home/matthias/vcs/github/CRED/rustc-ice-2026-03-04T08_23_51-1168850.txt` to your bug report
note: rustc 1.96.0-nightly (d933cf483 2026-03-04) running on x86_64-unknown-linux-gnu
note: compiler flags: -Z threads=8
query stack during panic:
#0 [dyn_compatibility_violations] determining dyn-compatibility of trait `B`
#1 [is_dyn_compatible] checking if trait `B` is dyn-compatible
#2 [fn_sig] computing function signature of `A::g`
#3 [check_well_formed] checking that `A::g` is well-formed
#4 [check_type_wf] checking that types are well-formed
#5 [analysis] running analysis passes on crate `code`
end of query stack
warning: 1 warning emitted
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[E0391]: cycle detected when computing function signature of `A::g`
--> code.rs:4:5
|
4 | fn g() -> B;
| ^^^^^^^^^^^^
|
note: ...which requires checking if trait `B` is dyn-compatible...
--> code.rs:7:1
|
7 | trait B {
| ^^^^^^^
note: ...which requires determining dyn-compatibility of trait `B`...
--> code.rs:7:1
|
7 | trait B {
| ^^^^^^^
note: ...which requires computing function signature of `B::bar`...
--> code.rs:8:5
|
8 | fn bar(&self, x: &A);
| ^^^^^^^^^^^^^^^^^^^^^
note: ...which requires checking if trait `A` is dyn-compatible...
--> code.rs:3:1
|
3 | trait A {
| ^^^^^^^
note: ...which requires determining dyn-compatibility of trait `A`...
--> code.rs:3:1
|
3 | trait A {
| ^^^^^^^
= note: ...which again requires computing function signature of `A::g`, completing the cycle
note: cycle used when checking that `A::g` is well-formed
--> code.rs:4:5
|
4 | fn g() -> B;
| ^^^^^^^^^^^^
= 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 /rustc-dev/d933cf483edf1605142ac6899ff32536c0ad8b22/compiler/rustc_query_impl/src/job.rs:482:16
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_impl::execution::mk_cycle::<rustc_middle::query::caches::DefIdCache<rustc_middle::query::erase::ErasedData<[u8; 24]>>>
5: rustc_query_impl::execution::try_execute_query::<rustc_middle::query::caches::DefIdCache<rustc_middle::query::erase::ErasedData<[u8; 24]>>, false>
6: rustc_query_impl::query_impl::fn_sig::execute_query_non_incr::__rust_end_short_backtrace
7: rustc_trait_selection::traits::dyn_compatibility::virtual_call_violations_for_method
8: rustc_trait_selection::traits::dyn_compatibility::dyn_compatibility_violations_for_assoc_item
9: <core::iter::adapters::flatten::FlatMap<core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<(core::option::Option<rustc_span::symbol::Symbol>, rustc_middle::ty::assoc::AssocItem)>, <rustc_data_structures::sorted_map::index_map::SortedIndexMultiMap<u32, core::option::Option<rustc_span::symbol::Symbol>, rustc_middle::ty::assoc::AssocItem>>::iter::{closure#0}>, <rustc_middle::ty::assoc::AssocItems>::in_definition_order::{closure#0}>, alloc::vec::Vec<rustc_middle::traits::DynCompatibilityViolation>, rustc_trait_selection::traits::dyn_compatibility::dyn_compatibility_violations_for_trait::{closure#0}::{closure#0}> as core::iter::traits::iterator::Iterator>::next
10: <core::iter::adapters::GenericShunt<core::iter::adapters::map::Map<core::iter::adapters::flatten::FlatMap<core::iter::sources::from_fn::FromFn<rustc_type_ir::elaborate::supertrait_def_ids<rustc_middle::ty::context::TyCtxt>::{closure#0}>, alloc::vec::Vec<rustc_middle::traits::DynCompatibilityViolation>, rustc_trait_selection::traits::dyn_compatibility::dyn_compatibility_violations::{closure#0}>, core::result::Result<rustc_middle::traits::DynCompatibilityViolation, !>::Ok>, core::result::Result<core::convert::Infallible, !>> as core::iter::traits::iterator::Iterator>::next
11: rustc_trait_selection::traits::dyn_compatibility::dyn_compatibility_violations
12: rustc_query_impl::query_impl::dyn_compatibility_violations::invoke_provider_fn::__rust_begin_short_backtrace
13: rustc_query_impl::execution::try_execute_query::<rustc_middle::query::caches::DefIdCache<rustc_middle::query::erase::ErasedData<[u8; 16]>>, false>
14: rustc_query_impl::query_impl::dyn_compatibility_violations::execute_query_non_incr::__rust_end_short_backtrace
15: rustc_trait_selection::traits::dyn_compatibility::is_dyn_compatible
16: rustc_query_impl::query_impl::is_dyn_compatible::invoke_provider_fn::__rust_begin_short_backtrace
17: rustc_query_impl::execution::try_execute_query::<rustc_middle::query::caches::DefIdCache<rustc_middle::query::erase::ErasedData<[u8; 1]>>, false>
18: rustc_query_impl::query_impl::is_dyn_compatible::execute_query_non_incr::__rust_end_short_backtrace
19: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::prohibit_or_lint_bare_trait_object_ty
20: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_trait_object_ty
21: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_ty
22: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_fn_ty
23: rustc_hir_analysis::collect::fn_sig
24: rustc_query_impl::query_impl::fn_sig::invoke_provider_fn::__rust_begin_short_backtrace
25: rustc_query_impl::execution::try_execute_query::<rustc_middle::query::caches::DefIdCache<rustc_middle::query::erase::ErasedData<[u8; 24]>>, false>
26: rustc_query_impl::query_impl::fn_sig::execute_query_non_incr::__rust_end_short_backtrace
27: rustc_hir_analysis::check::check::check_item_type
28: rustc_hir_analysis::check::wfcheck::check_well_formed
29: rustc_query_impl::query_impl::check_well_formed::invoke_provider_fn::__rust_begin_short_backtrace
30: rustc_query_impl::execution::try_execute_query::<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::ErasedData<[u8; 1]>, rustc_middle::dep_graph::graph::DepNodeIndex>, false>
31: rustc_query_impl::query_impl::check_well_formed::execute_query_non_incr::__rust_end_short_backtrace
32: <rustc_middle::hir::ModuleItems>::par_opaques::<rustc_hir_analysis::check::wfcheck::check_type_wf::{closure#5}>::{closure#0}
33: <rustc_thread_pool::job::HeapJob<<rustc_thread_pool::scope::Scope>::spawn<rustc_data_structures::sync::parallel::par_slice<&rustc_span::def_id::LocalDefId, rustc_data_structures::sync::parallel::try_par_for_each_in<&[rustc_span::def_id::LocalDefId], rustc_span::ErrorGuaranteed, <rustc_middle::hir::ModuleItems>::par_opaques<rustc_hir_analysis::check::wfcheck::check_type_wf::{closure#5}>::{closure#0}>::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>::{closure#0}> as rustc_thread_pool::job::Job>::execute
34: <rustc_thread_pool::registry::WorkerThread>::wait_or_steal_until_cold
35: <rustc_thread_pool::registry::ThreadBuilder>::run
36: std::sys::backtrace::__rust_begin_short_backtrace::<<rustc_thread_pool::ThreadPoolBuilder>::build_scoped<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
37: <std::thread::lifecycle::spawn_unchecked<<rustc_thread_pool::ThreadPoolBuilder>::build_scoped<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#0}, rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#5}::{closure#0}::{closure#1}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
38: <std::sys::thread::unix::Thread>::new::thread_start
39: <unknown>
40: <unknown>
--> code.rs:4:5
|
4 | fn g() -> B;
| ^^^^^^^^^^^^
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 `/home/matthias/vcs/github/CRED/rustc-ice-2026-03-04T08_23_51-1168850.txt` to your bug report
note: rustc 1.96.0-nightly (d933cf483 2026-03-04) running on x86_64-unknown-linux-gnu
note: compiler flags: -Z threads=8
query stack during panic:
end of query stack
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