Future in trait_alias causes internal compiler error ?

[kanarus]

Code

#![feature(trait_alias)]
use futures::Future;

trait F<Fut: Future<Output = usize>> = Fn() -> Fut;
fn f<Fut>(a: dyn F<Fut>) {}

fn main() {}

Meta

• rustc --version --verbose:

rustc 1.67.0-nightly (1286ee23e 2022-11-05)
binary: rustc
commit-hash: 1286ee23e4e2dec8c1696d3d76c6b26d97bbcf82
commit-date: 2022-11-05
host: aarch64-apple-darwin
release: 1.67.0-nightly
LLVM version: 15.0.4

• Moving <Fut: Future<Output = usize>> to where-clause (e.g. where Fut: Future<Output = usize>) doesn't change the result
• Some part of code analyzing of rust-analyzer seems to stop at dyn F<Fut>. For example, when we add some "plausible" arguments like b: F, c: Fn after a: dyn F<Fut>, rust-analyzer doesn't report any mistakes.
• When replacing Future<Output = usize> with non-Future trait like ToString, everything get fine:
  • rust-analyzer reports "the size for values of type (dyn Fn() -> Fut + 'static) cannot be known at compilation time" caused by rustc
  • and adding & to dyn F<Fut> makes it compilable

Error output

cargo build:

   Compiling x v0.1.0 (/Users/kanarus/Projects/experiment-of-cargo)
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Fut`,
 right: `FreshTy(0)`', compiler/rustc_hir_analysis/src/astconv/mod.rs:1510:17
stack backtrace:
   0:        0x104a37d00 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::haf3883fade86d22d
   1:        0x104a8283c - core::fmt::write::h586369edc3d621be
   2:        0x104a2a910 - std::io::Write::write_fmt::hd49c8a766dbe1256
   3:        0x104a37b14 - std::sys_common::backtrace::print::hb2a6b9b8cd29df68
   4:        0x104a3a668 - std::panicking::default_hook::{{closure}}::hbfa33fc78d6bc544
   5:        0x104a3a3c0 - std::panicking::default_hook::h3f44e70bec5b9a68
   6:        0x10c9779f4 - rustc_driver[d28aa724c6ee2406]::DEFAULT_HOOK::{closure#0}::{closure#0}
   7:        0x104a3ad78 - std::panicking::rust_panic_with_hook::h5b5580e1021d3f8b
   8:        0x104a3ab60 - std::panicking::begin_panic_handler::{{closure}}::h35bf90c35f5bee31
   9:        0x104a38168 - std::sys_common::backtrace::__rust_end_short_backtrace::hf097075f6803994a
  10:        0x104a3a8b4 - _rust_begin_unwind
  11:        0x104aae1f8 - core::panicking::panic_fmt::h48dfe143742508dc
  12:        0x104a7fc5c - core::panicking::assert_failed_inner::h6ffba988bc5fafcf
  13:        0x110ae5e50 - core[d1f3415165dba3f6]::panicking::assert_failed::<rustc_middle[d0475add3887dfd3]::ty::Ty, rustc_middle[d0475add3887dfd3]::ty::Ty>
  14:        0x10ee71038 - <rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::ProjectionPredicate>>::map_bound::<<dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#13}::{closure#0}, rustc_middle[d0475add3887dfd3]::ty::sty::ExistentialProjection>
  15:        0x10ee6a21c - <core[d1f3415165dba3f6]::iter::adapters::chain::Chain<core[d1f3415165dba3f6]::iter::adapters::chain::Chain<core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::slice::iter::Iter<rustc_trait_selection[f4ea8686592e16cc]::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#12}>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#14}>, core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::slice::iter::Iter<(rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::ProjectionPredicate>, rustc_span[36d9a4cdbe26759f]::span_encoding::Span)>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#13}>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#16}>>, core[d1f3415165dba3f6]::iter::adapters::map::Map<alloc[65e608ada264bb2d]::vec::into_iter::IntoIter<rustc_trait_selection[f4ea8686592e16cc]::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#15}>> as core[d1f3415165dba3f6]::iter::traits::iterator::Iterator>::next
  16:        0x10ee62424 - <smallvec[87ab3001f96c7bc7]::SmallVec<[rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::sty::ExistentialPredicate>; 8usize]> as core[d1f3415165dba3f6]::iter::traits::collect::Extend<rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::sty::ExistentialPredicate>>>::extend::<core[d1f3415165dba3f6]::iter::adapters::chain::Chain<core[d1f3415165dba3f6]::iter::adapters::chain::Chain<core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::slice::iter::Iter<rustc_trait_selection[f4ea8686592e16cc]::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#12}>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#14}>, core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::slice::iter::Iter<(rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::ProjectionPredicate>, rustc_span[36d9a4cdbe26759f]::span_encoding::Span)>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#13}>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#16}>>, core[d1f3415165dba3f6]::iter::adapters::map::Map<alloc[65e608ada264bb2d]::vec::into_iter::IntoIter<rustc_trait_selection[f4ea8686592e16cc]::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#15}>>>
  17:        0x10ef2da88 - <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::conv_object_ty_poly_trait_ref
  18:        0x10ef42168 - <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::ast_ty_to_ty_inner::{closure#0}
  19:        0x10eede5b4 - <core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::enumerate::Enumerate<core[d1f3415165dba3f6]::slice::iter::Iter<rustc_hir[e9c00d8902f14da9]::hir::Ty>>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::ty_of_fn::{closure#0}::{closure#0}> as core[d1f3415165dba3f6]::iter::traits::iterator::Iterator>::fold::<(), core[d1f3415165dba3f6]::iter::traits::iterator::Iterator::for_each::call<rustc_middle[d0475add3887dfd3]::ty::Ty, <alloc[65e608ada264bb2d]::vec::Vec<rustc_middle[d0475add3887dfd3]::ty::Ty> as alloc[65e608ada264bb2d]::vec::spec_extend::SpecExtend<rustc_middle[d0475add3887dfd3]::ty::Ty, core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::enumerate::Enumerate<core[d1f3415165dba3f6]::slice::iter::Iter<rustc_hir[e9c00d8902f14da9]::hir::Ty>>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::ty_of_fn::{closure#0}::{closure#0}>>>::spec_extend::{closure#0}>::{closure#0}>
  20:        0x10ee3ade4 - <alloc[65e608ada264bb2d]::vec::Vec<rustc_middle[d0475add3887dfd3]::ty::Ty> as alloc[65e608ada264bb2d]::vec::spec_from_iter::SpecFromIter<rustc_middle[d0475add3887dfd3]::ty::Ty, core[d1f3415165dba3f6]::iter::adapters::map::Map<core[d1f3415165dba3f6]::iter::adapters::enumerate::Enumerate<core[d1f3415165dba3f6]::slice::iter::Iter<rustc_hir[e9c00d8902f14da9]::hir::Ty>>, <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::ty_of_fn::{closure#0}::{closure#0}>>>::from_iter
  21:        0x10ef424f8 - <dyn rustc_hir_analysis[9bb8dc090afd8a]::astconv::AstConv>::ty_of_fn::{closure#0}
  22:        0x10eec723c - rustc_hir_analysis[9bb8dc090afd8a]::collect::infer_return_ty_for_fn_sig
  23:        0x10eed122c - rustc_hir_analysis[9bb8dc090afd8a]::collect::fn_sig
  24:        0x10fbfa61c - <rustc_query_system[3340307952f6e132]::dep_graph::graph::DepGraph<rustc_middle[d0475add3887dfd3]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[d0475add3887dfd3]::ty::context::TyCtxt, rustc_span[36d9a4cdbe26759f]::def_id::DefId, rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::sty::FnSig>>
  25:        0x10f9a0288 - rustc_query_system[3340307952f6e132]::query::plumbing::try_execute_query::<rustc_query_impl[fb2515e7d176a9bb]::plumbing::QueryCtxt, rustc_query_system[3340307952f6e132]::query::caches::DefaultCache<rustc_span[36d9a4cdbe26759f]::def_id::DefId, rustc_middle[d0475add3887dfd3]::ty::sty::Binder<rustc_middle[d0475add3887dfd3]::ty::sty::FnSig>>>
  26:        0x10fa59928 - rustc_query_system[3340307952f6e132]::query::plumbing::get_query::<rustc_query_impl[fb2515e7d176a9bb]::queries::fn_sig, rustc_query_impl[fb2515e7d176a9bb]::plumbing::QueryCtxt>
  27:        0x10faeeee8 - <rustc_query_impl[fb2515e7d176a9bb]::Queries as rustc_middle[d0475add3887dfd3]::ty::query::QueryEngine>::fn_sig
  28:        0x10eec4eb4 - rustc_hir_analysis[9bb8dc090afd8a]::collect::convert_item
  29:        0x10eebeba4 - <rustc_hir_analysis[9bb8dc090afd8a]::collect::CollectItemTypesVisitor as rustc_hir[e9c00d8902f14da9]::intravisit::Visitor>::visit_item
  30:        0x10ee7a480 - <rustc_middle[d0475add3887dfd3]::hir::map::Map>::visit_item_likes_in_module::<rustc_hir_analysis[9bb8dc090afd8a]::collect::CollectItemTypesVisitor>
  31:        0x10eebe2a4 - rustc_hir_analysis[9bb8dc090afd8a]::collect::collect_mod_item_types
  32:        0x10fbf9ca4 - <rustc_query_system[3340307952f6e132]::dep_graph::graph::DepGraph<rustc_middle[d0475add3887dfd3]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[d0475add3887dfd3]::ty::context::TyCtxt, rustc_span[36d9a4cdbe26759f]::def_id::LocalDefId, ()>
  33:        0x10f98d144 - rustc_query_system[3340307952f6e132]::query::plumbing::try_execute_query::<rustc_query_impl[fb2515e7d176a9bb]::plumbing::QueryCtxt, rustc_query_system[3340307952f6e132]::query::caches::DefaultCache<rustc_span[36d9a4cdbe26759f]::def_id::LocalDefId, ()>>
  34:        0x10fa4d504 - rustc_query_system[3340307952f6e132]::query::plumbing::get_query::<rustc_query_impl[fb2515e7d176a9bb]::queries::collect_mod_item_types, rustc_query_impl[fb2515e7d176a9bb]::plumbing::QueryCtxt>
  35:        0x10ee79cbc - <rustc_middle[d0475add3887dfd3]::hir::map::Map>::for_each_module::<rustc_hir_analysis[9bb8dc090afd8a]::check_crate::{closure#0}::{closure#0}::{closure#0}>
  36:        0x10ee6e58c - <rustc_session[e361cb92ae51219d]::session::Session>::track_errors::<rustc_hir_analysis[9bb8dc090afd8a]::check_crate::{closure#0}, ()>
  37:        0x10ee26264 - rustc_hir_analysis[9bb8dc090afd8a]::check_crate
  38:        0x10ca917dc - rustc_interface[30e974206ea86b74]::passes::analysis
  39:        0x10fc21c68 - <rustc_query_system[3340307952f6e132]::dep_graph::graph::DepGraph<rustc_middle[d0475add3887dfd3]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[d0475add3887dfd3]::ty::context::TyCtxt, (), core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>
  40:        0x10f9f0c50 - rustc_query_system[3340307952f6e132]::query::plumbing::try_execute_query::<rustc_query_impl[fb2515e7d176a9bb]::plumbing::QueryCtxt, rustc_query_system[3340307952f6e132]::query::caches::DefaultCache<(), core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>>
  41:        0x10fa59ff4 - rustc_query_system[3340307952f6e132]::query::plumbing::get_query::<rustc_query_impl[fb2515e7d176a9bb]::queries::analysis, rustc_query_impl[fb2515e7d176a9bb]::plumbing::QueryCtxt>
  42:        0x10c98fd70 - <rustc_interface[30e974206ea86b74]::passes::QueryContext>::enter::<rustc_driver[d28aa724c6ee2406]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>
  43:        0x10c9cc708 - rustc_span[36d9a4cdbe26759f]::with_source_map::<core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>, rustc_interface[30e974206ea86b74]::interface::run_compiler<core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>, rustc_driver[d28aa724c6ee2406]::run_compiler::{closure#1}>::{closure#0}::{closure#1}>
  44:        0x10c9be614 - <scoped_tls[a0d75c10d139911f]::ScopedKey<rustc_span[36d9a4cdbe26759f]::SessionGlobals>>::set::<rustc_interface[30e974206ea86b74]::interface::run_compiler<core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>, rustc_driver[d28aa724c6ee2406]::run_compiler::{closure#1}>::{closure#0}, core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>
  45:        0x10c9930fc - std[68109d43c3ebdd4c]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[30e974206ea86b74]::util::run_in_thread_pool_with_globals<rustc_interface[30e974206ea86b74]::interface::run_compiler<core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>, rustc_driver[d28aa724c6ee2406]::run_compiler::{closure#1}>::{closure#0}, core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>
  46:        0x10c97ca20 - <<std[68109d43c3ebdd4c]::thread::Builder>::spawn_unchecked_<rustc_interface[30e974206ea86b74]::util::run_in_thread_pool_with_globals<rustc_interface[30e974206ea86b74]::interface::run_compiler<core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>, rustc_driver[d28aa724c6ee2406]::run_compiler::{closure#1}>::{closure#0}, core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d1f3415165dba3f6]::result::Result<(), rustc_errors[6317447bb9fda403]::ErrorGuaranteed>>::{closure#1} as core[d1f3415165dba3f6]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  47:        0x104a42dc4 - std::sys::unix::thread::Thread::new::thread_start::h1d785310ca00b7ad
  48:        0x1a841e06c - __pthread_deallocate

error: internal compiler error: unexpected panic

note: 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: rustc 1.67.0-nightly (1286ee23e 2022-11-05) running on aarch64-apple-darwin

note: compiler flags: --crate-type bin -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental=[REDACTED]

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [fn_sig] computing function signature of `f`
#1 [collect_mod_item_types] collecting item types in top-level module
#2 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `x`

Backtrace

`RUST_BACKTRACE=1 cargo build`:

   Compiling x v0.1.0 (/Users/kanarus/Projects/experiment-of-cargo)
thread 'rustc' panicked at 'assertion failed: `(left == right)`
  left: `Fut`,
 right: `FreshTy(0)`', compiler/rustc_hir_analysis/src/astconv/mod.rs:1510:17
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed::<rustc_middle::ty::Ty, rustc_middle::ty::Ty>
   4: <rustc_middle::ty::sty::Binder<rustc_middle::ty::ProjectionPredicate>>::map_bound::<<dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#13}::{closure#0}, rustc_middle::ty::sty::ExistentialProjection>
   5: <core::iter::adapters::chain::Chain<core::iter::adapters::chain::Chain<core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<rustc_trait_selection::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#12}>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#14}>, core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<(rustc_middle::ty::sty::Binder<rustc_middle::ty::ProjectionPredicate>, rustc_span::span_encoding::Span)>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#13}>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#16}>>, core::iter::adapters::map::Map<alloc::vec::into_iter::IntoIter<rustc_trait_selection::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#15}>> as core::iter::traits::iterator::Iterator>::next
   6: <smallvec::SmallVec<[rustc_middle::ty::sty::Binder<rustc_middle::ty::sty::ExistentialPredicate>; 8]> as core::iter::traits::collect::Extend<rustc_middle::ty::sty::Binder<rustc_middle::ty::sty::ExistentialPredicate>>>::extend::<core::iter::adapters::chain::Chain<core::iter::adapters::chain::Chain<core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<rustc_trait_selection::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#12}>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#14}>, core::iter::adapters::map::Map<core::iter::adapters::map::Map<core::slice::iter::Iter<(rustc_middle::ty::sty::Binder<rustc_middle::ty::ProjectionPredicate>, rustc_span::span_encoding::Span)>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#13}>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#16}>>, core::iter::adapters::map::Map<alloc::vec::into_iter::IntoIter<rustc_trait_selection::traits::util::TraitAliasExpansionInfo>, <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref::{closure#15}>>>
   7: <dyn rustc_hir_analysis::astconv::AstConv>::conv_object_ty_poly_trait_ref
   8: <dyn rustc_hir_analysis::astconv::AstConv>::ast_ty_to_ty_inner::{closure#0}
   9: <core::iter::adapters::map::Map<core::iter::adapters::enumerate::Enumerate<core::slice::iter::Iter<rustc_hir::hir::Ty>>, <dyn rustc_hir_analysis::astconv::AstConv>::ty_of_fn::{closure#0}::{closure#0}> as core::iter::traits::iterator::Iterator>::fold::<(), core::iter::traits::iterator::Iterator::for_each::call<rustc_middle::ty::Ty, <alloc::vec::Vec<rustc_middle::ty::Ty> as alloc::vec::spec_extend::SpecExtend<rustc_middle::ty::Ty, core::iter::adapters::map::Map<core::iter::adapters::enumerate::Enumerate<core::slice::iter::Iter<rustc_hir::hir::Ty>>, <dyn rustc_hir_analysis::astconv::AstConv>::ty_of_fn::{closure#0}::{closure#0}>>>::spec_extend::{closure#0}>::{closure#0}>
  10: <alloc::vec::Vec<rustc_middle::ty::Ty> as alloc::vec::spec_from_iter::SpecFromIter<rustc_middle::ty::Ty, core::iter::adapters::map::Map<core::iter::adapters::enumerate::Enumerate<core::slice::iter::Iter<rustc_hir::hir::Ty>>, <dyn rustc_hir_analysis::astconv::AstConv>::ty_of_fn::{closure#0}::{closure#0}>>>::from_iter
  11: <dyn rustc_hir_analysis::astconv::AstConv>::ty_of_fn::{closure#0}
  12: rustc_hir_analysis::collect::infer_return_ty_for_fn_sig
  13: rustc_hir_analysis::collect::fn_sig
  14: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, rustc_span::def_id::DefId, rustc_middle::ty::sty::Binder<rustc_middle::ty::sty::FnSig>>
  15: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::DefId, rustc_middle::ty::sty::Binder<rustc_middle::ty::sty::FnSig>>>
  16: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::fn_sig, rustc_query_impl::plumbing::QueryCtxt>
  17: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::fn_sig
  18: rustc_hir_analysis::collect::convert_item
  19: <rustc_hir_analysis::collect::CollectItemTypesVisitor as rustc_hir::intravisit::Visitor>::visit_item
  20: <rustc_middle::hir::map::Map>::visit_item_likes_in_module::<rustc_hir_analysis::collect::CollectItemTypesVisitor>
  21: rustc_hir_analysis::collect::collect_mod_item_types
  22: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, rustc_span::def_id::LocalDefId, ()>
  23: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<rustc_span::def_id::LocalDefId, ()>>
  24: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::collect_mod_item_types, rustc_query_impl::plumbing::QueryCtxt>
  25: <rustc_middle::hir::map::Map>::for_each_module::<rustc_hir_analysis::check_crate::{closure#0}::{closure#0}::{closure#0}>
  26: <rustc_session::session::Session>::track_errors::<rustc_hir_analysis::check_crate::{closure#0}, ()>
  27: rustc_hir_analysis::check_crate
  28: rustc_interface::passes::analysis
  29: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, (), core::result::Result<(), rustc_errors::ErrorGuaranteed>>
  30: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), core::result::Result<(), rustc_errors::ErrorGuaranteed>>>
  31: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::analysis, rustc_query_impl::plumbing::QueryCtxt>
  32: <rustc_interface::passes::QueryContext>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}::{closure#3}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
  33: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}::{closure#1}>
  34: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorGuaranteed>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorGuaranteed>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

note: 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: rustc 1.67.0-nightly (1286ee23e 2022-11-05) running on aarch64-apple-darwin

note: compiler flags: --crate-type bin -C embed-bitcode=no -C split-debuginfo=unpacked -C debuginfo=2 -C incremental=[REDACTED]

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [fn_sig] computing function signature of `f`
#1 [collect_mod_item_types] collecting item types in top-level module
#2 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `x`