ICE: `Layout::compute: unexpected type '_'`

[matthiaskrgr]

Code

#![feature(transmutability)]
#![feature(type_alias_impl_trait)]
trait OpaqueTrait {}
type OpaqueType = impl OpaqueTrait;
trait AnotherTrait {}
impl<T: std::mem::BikeshedIntrinsicFrom<(), ()>> AnotherTrait for T {}
impl AnotherTrait for OpaqueType {}
pub fn main() {}

Meta

rustc --version --verbose:

rustc 1.79.0-nightly (f9b161492 2024-04-19)
binary: rustc
commit-hash: f9b16149208c8a8a349c32813312716f6603eb6f
commit-date: 2024-04-19
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.4

Error output

error: unconstrained opaque type
 --> a.rs:4:19
  |
4 | type OpaqueType = impl OpaqueTrait;
  |                   ^^^^^^^^^^^^^^^^
  |
  = note: `OpaqueType` must be used in combination with a concrete type within the same module

error[E0747]: type provided when a constant was expected
 --> a.rs:6:45
  |
6 | impl<T: std::mem::BikeshedIntrinsicFrom<(), ()>> AnotherTrait for T {}
  |                                             ^^

Backtrace

error: internal compiler error: compiler/rustc_ty_utils/src/layout.rs:676:13: Layout::compute: unexpected type `_`

thread 'rustc' panicked at compiler/rustc_ty_utils/src/layout.rs:676:13:
Box<dyn Any>
stack backtrace:
   0:     0x770d87853a75 - std::backtrace_rs::backtrace::libunwind::trace::ha83ac36f3d576216
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x770d87853a75 - std::backtrace_rs::backtrace::trace_unsynchronized::hb98e29c033b56d71
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x770d87853a75 - std::sys_common::backtrace::_print_fmt::h9cac98576a93da05
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x770d87853a75 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hc08cb2c96bc6af47
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x770d878a2ceb - core::fmt::rt::Argument::fmt::h7e0e829b93f0d534
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/core/src/fmt/rt.rs:165:63
   5:     0x770d878a2ceb - core::fmt::write::hc94efcaace3d21b0
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/core/src/fmt/mod.rs:1157:21
   6:     0x770d878485ff - std::io::Write::write_fmt::h04b543bbaa6f2dd7
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/io/mod.rs:1832:15
   7:     0x770d8785384e - std::sys_common::backtrace::_print::hee1e9db3a2945572
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x770d8785384e - std::sys_common::backtrace::print::h6c7cba00911f4786
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x770d878561b9 - std::panicking::default_hook::{{closure}}::ha7d58c0a2e775af5
  10:     0x770d87855efd - std::panicking::default_hook::h87a09229bb1730d2
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/panicking.rs:298:9
  11:     0x770d8421a4bc - std[b1a6245f99d026e2]::panicking::update_hook::<alloc[ffa384fe5a6ae168]::boxed::Box<rustc_driver_impl[5ebafc17f6baf5ac]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x770d878568b6 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h5e2a6d4eae799185
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/alloc/src/boxed.rs:2036:9
  13:     0x770d878568b6 - std::panicking::rust_panic_with_hook::hd810693d9a8c8478
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/panicking.rs:799:13
  14:     0x770d84249f84 - std[b1a6245f99d026e2]::panicking::begin_panic::<rustc_errors[ba5989c8493379f8]::ExplicitBug>::{closure#0}
  15:     0x770d84246936 - std[b1a6245f99d026e2]::sys_common::backtrace::__rust_end_short_backtrace::<std[b1a6245f99d026e2]::panicking::begin_panic<rustc_errors[ba5989c8493379f8]::ExplicitBug>::{closure#0}, !>
  16:     0x770d84241f06 - std[b1a6245f99d026e2]::panicking::begin_panic::<rustc_errors[ba5989c8493379f8]::ExplicitBug>
  17:     0x770d84252ea1 - <rustc_errors[ba5989c8493379f8]::diagnostic::BugAbort as rustc_errors[ba5989c8493379f8]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x770d846fcf9c - rustc_middle[e99f9e5b138cd7e6]::util::bug::opt_span_bug_fmt::<rustc_span[add96f0181708003]::span_encoding::Span>::{closure#0}
  19:     0x770d846e47fa - rustc_middle[e99f9e5b138cd7e6]::ty::context::tls::with_opt::<rustc_middle[e99f9e5b138cd7e6]::util::bug::opt_span_bug_fmt<rustc_span[add96f0181708003]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x770d846e467b - rustc_middle[e99f9e5b138cd7e6]::ty::context::tls::with_context_opt::<rustc_middle[e99f9e5b138cd7e6]::ty::context::tls::with_opt<rustc_middle[e99f9e5b138cd7e6]::util::bug::opt_span_bug_fmt<rustc_span[add96f0181708003]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x770d82ab2580 - rustc_middle[e99f9e5b138cd7e6]::util::bug::bug_fmt
  22:     0x770d85c63c6d - rustc_ty_utils[48d247cc516c592c]::layout::layout_of_uncached
  23:     0x770d85c55348 - rustc_ty_utils[48d247cc516c592c]::layout::layout_of
  24:     0x770d85c552d1 - rustc_query_impl[c33ec4ad6556889c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c33ec4ad6556889c]::query_impl::layout_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 16usize]>>
  25:     0x770d85c545b9 - rustc_query_system[4ce495e28c9907d2]::query::plumbing::try_execute_query::<rustc_query_impl[c33ec4ad6556889c]::DynamicConfig<rustc_query_system[4ce495e28c9907d2]::query::caches::DefaultCache<rustc_middle[e99f9e5b138cd7e6]::ty::ParamEnvAnd<rustc_middle[e99f9e5b138cd7e6]::ty::Ty>, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 16usize]>>, false, true, false>, rustc_query_impl[c33ec4ad6556889c]::plumbing::QueryCtxt, false>
  26:     0x770d85c54238 - rustc_query_impl[c33ec4ad6556889c]::query_impl::layout_of::get_query_non_incr::__rust_end_short_backtrace
  27:     0x770d84dc16fe - rustc_middle[e99f9e5b138cd7e6]::query::plumbing::query_get_at::<rustc_query_system[4ce495e28c9907d2]::query::caches::DefaultCache<rustc_middle[e99f9e5b138cd7e6]::ty::ParamEnvAnd<rustc_middle[e99f9e5b138cd7e6]::ty::Ty>, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 16usize]>>>
  28:     0x770d84ddd419 - <rustc_transmute[fa409bc515f85ab3]::maybe_transmutable::MaybeTransmutableQuery<rustc_middle[e99f9e5b138cd7e6]::ty::Ty, rustc_middle[e99f9e5b138cd7e6]::ty::context::TyCtxt>>::answer::{closure#0}
  29:     0x770d84ddab53 - <rustc_transmute[fa409bc515f85ab3]::rustc::TransmuteTypeEnv>::is_transmutable
  30:     0x770d85eb7ad3 - <rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::confirm_candidate
  31:     0x770d85a915cb - <rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::evaluate_candidate::{closure#0}::{closure#0}
  32:     0x770d82378af3 - <rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::candidate_from_obligation_no_cache
  33:     0x770d823b8b59 - <rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::candidate_from_obligation
  34:     0x770d85a94da0 - <rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::evaluate_trait_predicate_recursively
  35:     0x770d85a8522e - <rustc_infer[c524740c99df999d]::infer::InferCtxt>::probe::<core[4c074f95c636289]::result::Result<rustc_middle[e99f9e5b138cd7e6]::traits::select::EvaluationResult, rustc_middle[e99f9e5b138cd7e6]::traits::select::OverflowError>, <rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::evaluation_probe<<rustc_trait_selection[c82f91c0eb405fdf]::traits::select::SelectionContext>::evaluate_root_obligation::{closure#0}>::{closure#0}>
  36:     0x770d85a84201 - rustc_trait_selection[c82f91c0eb405fdf]::traits::coherence::overlap
  37:     0x770d823a0914 - <rustc_middle[e99f9e5b138cd7e6]::traits::specialization_graph::Children as rustc_trait_selection[c82f91c0eb405fdf]::traits::specialize::specialization_graph::ChildrenExt>::insert
  38:     0x770d832180e7 - <rustc_middle[e99f9e5b138cd7e6]::traits::specialization_graph::Graph as rustc_trait_selection[c82f91c0eb405fdf]::traits::specialize::specialization_graph::GraphExt>::insert
  39:     0x770d856b40bc - rustc_trait_selection[c82f91c0eb405fdf]::traits::specialize::specialization_graph_provider
  40:     0x770d856b3c1d - rustc_query_impl[c33ec4ad6556889c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c33ec4ad6556889c]::query_impl::specialization_graph_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 8usize]>>
  41:     0x770d856b65e1 - rustc_query_system[4ce495e28c9907d2]::query::plumbing::try_execute_query::<rustc_query_impl[c33ec4ad6556889c]::DynamicConfig<rustc_query_system[4ce495e28c9907d2]::query::caches::DefIdCache<rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[c33ec4ad6556889c]::plumbing::QueryCtxt, false>
  42:     0x770d85d8a65e - rustc_query_impl[c33ec4ad6556889c]::query_impl::specialization_graph_of::get_query_non_incr::__rust_end_short_backtrace
  43:     0x770d85ce3af1 - rustc_hir_analysis[465c838ed0c91715]::coherence::coherent_trait
  44:     0x770d85ce37f1 - rustc_query_impl[c33ec4ad6556889c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c33ec4ad6556889c]::query_impl::coherent_trait::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>
  45:     0x770d858371d0 - rustc_query_system[4ce495e28c9907d2]::query::plumbing::try_execute_query::<rustc_query_impl[c33ec4ad6556889c]::DynamicConfig<rustc_query_system[4ce495e28c9907d2]::query::caches::DefIdCache<rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[c33ec4ad6556889c]::plumbing::QueryCtxt, false>
  46:     0x770d85835d49 - rustc_query_impl[c33ec4ad6556889c]::query_impl::coherent_trait::get_query_non_incr::__rust_end_short_backtrace
  47:     0x770d85e4c61e - rustc_hir_analysis[465c838ed0c91715]::check::wfcheck::check_well_formed
  48:     0x770d85e4a3c7 - rustc_query_impl[c33ec4ad6556889c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c33ec4ad6556889c]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>
  49:     0x770d85e49b6a - rustc_query_system[4ce495e28c9907d2]::query::plumbing::try_execute_query::<rustc_query_impl[c33ec4ad6556889c]::DynamicConfig<rustc_query_system[4ce495e28c9907d2]::query::caches::VecCache<rustc_hir[5039c425fb71505b]::hir_id::OwnerId, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[c33ec4ad6556889c]::plumbing::QueryCtxt, false>
  50:     0x770d85e498d3 - rustc_query_impl[c33ec4ad6556889c]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  51:     0x770d85e47841 - rustc_hir_analysis[465c838ed0c91715]::check::wfcheck::check_mod_type_wf
  52:     0x770d85e47689 - rustc_query_impl[c33ec4ad6556889c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c33ec4ad6556889c]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>
  53:     0x770d860c4d46 - rustc_query_system[4ce495e28c9907d2]::query::plumbing::try_execute_query::<rustc_query_impl[c33ec4ad6556889c]::DynamicConfig<rustc_query_system[4ce495e28c9907d2]::query::caches::DefaultCache<rustc_span[add96f0181708003]::def_id::LocalModDefId, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[c33ec4ad6556889c]::plumbing::QueryCtxt, false>
  54:     0x770d860c4aff - rustc_query_impl[c33ec4ad6556889c]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
  55:     0x770d857f1247 - rustc_hir_analysis[465c838ed0c91715]::check_crate
  56:     0x770d85be39fa - rustc_interface[4d16e32404bcb20f]::passes::analysis
  57:     0x770d85be3555 - rustc_query_impl[c33ec4ad6556889c]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c33ec4ad6556889c]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>
  58:     0x770d863b50e5 - rustc_query_system[4ce495e28c9907d2]::query::plumbing::try_execute_query::<rustc_query_impl[c33ec4ad6556889c]::DynamicConfig<rustc_query_system[4ce495e28c9907d2]::query::caches::SingleCache<rustc_middle[e99f9e5b138cd7e6]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[c33ec4ad6556889c]::plumbing::QueryCtxt, false>
  59:     0x770d863b4e49 - rustc_query_impl[c33ec4ad6556889c]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  60:     0x770d862374d9 - rustc_interface[4d16e32404bcb20f]::interface::run_compiler::<core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>, rustc_driver_impl[5ebafc17f6baf5ac]::run_compiler::{closure#0}>::{closure#1}
  61:     0x770d86222367 - std[b1a6245f99d026e2]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[4d16e32404bcb20f]::util::run_in_thread_with_globals<rustc_interface[4d16e32404bcb20f]::util::run_in_thread_pool_with_globals<rustc_interface[4d16e32404bcb20f]::interface::run_compiler<core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>, rustc_driver_impl[5ebafc17f6baf5ac]::run_compiler::{closure#0}>::{closure#1}, core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>>::{closure#0}, core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>>
  62:     0x770d8622212a - <<std[b1a6245f99d026e2]::thread::Builder>::spawn_unchecked_<rustc_interface[4d16e32404bcb20f]::util::run_in_thread_with_globals<rustc_interface[4d16e32404bcb20f]::util::run_in_thread_pool_with_globals<rustc_interface[4d16e32404bcb20f]::interface::run_compiler<core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>, rustc_driver_impl[5ebafc17f6baf5ac]::run_compiler::{closure#0}>::{closure#1}, core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>>::{closure#0}, core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[4c074f95c636289]::result::Result<(), rustc_span[add96f0181708003]::ErrorGuaranteed>>::{closure#2} as core[4c074f95c636289]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  63:     0x770d8786078b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h51d53d77b032da76
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/alloc/src/boxed.rs:2022:9
  64:     0x770d8786078b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hd03902f6d1c8cd92
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/alloc/src/boxed.rs:2022:9
  65:     0x770d8786078b - std::sys::pal::unix::thread::Thread::new::thread_start::ha033681dd3a5d038
                               at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/library/std/src/sys/pal/unix/thread.rs:108:17
  66:     0x770d810a955a - <unknown>
  67:     0x770d81126a3c - <unknown>
  68:                0x0 - <unknown>

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 `/tmp/im/rustc-ice-2024-04-20T20_22_42-649638.txt` to your bug report

query stack during panic:
panicked at /rustc/f9b16149208c8a8a349c32813312716f6603eb6f/compiler/rustc_type_ir/src/ty_kind.rs:709:17:
thread panicked while processing panic. aborting.
[2]    649638 IOT instruction  rustc a.rs

[matthiaskrgr]

bisects to #123367