ICE: assertion left == right failed [Goal .. == [ ] #151306
Description
auto-reduced (treereduce-rust):
//@compile-flags: --edition=2024 -Znext-solver=globally
pub trait Bar<'a>: 'a {
async fn new() -> (Self, impl Fn<()>) {
(Manager, async {})
}
}original:
// Test inherent trait impls work cross-crait.
pub trait Bar<'a> : 'a {
#[path = "bar.rs"]
pub(in crate::outer::nested) async fn new() -> (Self, impl Fn<()>) {
(Manager, async {})
}
}
impl<'a> dyn Bar<'a> {
pub fn bar(&self) {}
}Version information
rustc 1.95.0-nightly (621d76794 2026-01-18)
binary: rustc
commit-hash: 621d76794c76fc21c0a6151fbc090120e0230a91
commit-date: 2026-01-18
host: x86_64-unknown-linux-gnu
release: 1.95.0-nightly
LLVM version: 21.1.8
Possibly related line of code:
rust/compiler/rustc_trait_selection/src/solve/normalize.rs
Lines 44 to 56 in 621d767
Command:
/home/matthias/.rustup/toolchains/master/bin/rustc --edition=2024 -Znext-solver=globally
Program output
error[E0425]: cannot find value `Manager` in this scope
--> /tmp/icemaker_global_tempdir.YDdl8F0LMDj2/rustc_testrunner_tmpdir_reporting.FN1b6A2Nkcu9/mvce.rs:3:10
|
3 | (Manager, async {})
| ^^^^^^^ not found in this scope
error[E0601]: `main` function not found in crate `mvce`
--> /tmp/icemaker_global_tempdir.YDdl8F0LMDj2/rustc_testrunner_tmpdir_reporting.FN1b6A2Nkcu9/mvce.rs:5:2
|
5 | }
| ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.YDdl8F0LMDj2/rustc_testrunner_tmpdir_reporting.FN1b6A2Nkcu9/mvce.rs`
error[E0658]: the precise format of `Fn`-family traits' type parameters is subject to change
--> /tmp/icemaker_global_tempdir.YDdl8F0LMDj2/rustc_testrunner_tmpdir_reporting.FN1b6A2Nkcu9/mvce.rs:2:35
|
2 | async fn new() -> (Self, impl Fn<()>) {
| ^^^^^^ help: use parenthetical notation instead: `Fn() -> ()`
|
= note: see issue #29625 <https://github.com/rust-lang/rust/issues/29625> for more information
= help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
= note: this compiler was built on 2026-01-18; consider upgrading it if it is out of date
error[E0277]: the size for values of type `Self` cannot be known at compilation time
--> /tmp/icemaker_global_tempdir.YDdl8F0LMDj2/rustc_testrunner_tmpdir_reporting.FN1b6A2Nkcu9/mvce.rs:2:23
|
2 | async fn new() -> (Self, impl Fn<()>) {
| ^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
= note: only the last element of a tuple may have a dynamically sized type
help: consider further restricting `Self`
|
1 | pub trait Bar<'a>: 'a + Sized {
| +++++++
error[E0308]: mismatched types
--> /tmp/icemaker_global_tempdir.YDdl8F0LMDj2/rustc_testrunner_tmpdir_reporting.FN1b6A2Nkcu9/mvce.rs:2:43
|
2 | async fn new() -> (Self, impl Fn<()>) {
| ___________________________________________^
3 | | (Manager, async {})
4 | | }
| |_____^ types differ
|
= note: expected associated type `impl Future<Output = (Self, impl Fn<()>)>`
found `async` fn body `{async fn body of <Self as Bar<'a>>::new()}`
thread 'rustc' (1101311) panicked at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:50:5:
assertion `left == right` failed
left: [Goal { param_env: ParamEnv { caller_bounds: [Binder { value: ProjectionPredicate(AliasTerm { args: [Self/#0, 'a/#1, 'a/#1], def_id: DefId(0:11 ~ mvce[a621]::Bar::new::{anon_assoc#1}), .. }, Term::Ty(Alias(Opaque, AliasTy { args: [Self/#0, 'a/#1, 'a/#1], def_id: DefId(0:7 ~ mvce[a621]::Bar::new::{opaque#0}::{opaque#0}), .. }))), bound_vars: [] }, Binder { value: ProjectionPredicate(AliasTerm { args: [Self/#0, 'a/#1, 'a/#1], def_id: DefId(0:10 ~ mvce[a621]::Bar::new::{anon_assoc#0}), .. }, Term::Ty(Alias(Opaque, AliasTy { args: [Self/#0, 'a/#1, 'a/#1], def_id: DefId(0:6 ~ mvce[a621]::Bar::new::{opaque#0}), .. }))), bound_vars: [] }, Binder { value: TraitPredicate(<Self as Bar<'a>>, polarity:Positive), bound_vars: [] }, Binder { value: TraitPredicate(<Self as std::marker::MetaSized>, polarity:Positive), bound_vars: [] }, Binder { value: OutlivesPredicate(Self/#0, 'a/#1), bound_vars: [] }] }, predicate: Binder { value: AliasRelate(Term::Ty(Alias(Projection, AliasTy { args: [Self/#0, 'a/#1, 'a/#1], def_id: DefId(0:10 ~ mvce[a621]::Bar::new::{anon_assoc#0}), .. })), Equate, Term::Ty(?353t)), bound_vars: [] } }]
right: []
stack backtrace:
0: 0x7f5390833fd3 - <<std[287527946f71f0bc]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[7477a31a1a34cc49]::fmt::Display>::fmt
1: 0x7f5390e0e2c8 - core[7477a31a1a34cc49]::fmt::write
2: 0x7f539084a9c6 - <std[287527946f71f0bc]::sys::stdio::unix::Stderr as std[287527946f71f0bc]::io::Write>::write_fmt
3: 0x7f539080a048 - std[287527946f71f0bc]::panicking::default_hook::{closure#0}
4: 0x7f5390827703 - std[287527946f71f0bc]::panicking::default_hook
5: 0x7f538f7fbb8a - std[287527946f71f0bc]::panicking::update_hook::<alloc[979041e9952e771b]::boxed::Box<rustc_driver_impl[517260a07841a630]::install_ice_hook::{closure#1}>>::{closure#0}
6: 0x7f53908279e2 - std[287527946f71f0bc]::panicking::panic_with_hook
7: 0x7f539080a108 - std[287527946f71f0bc]::panicking::panic_handler::{closure#0}
8: 0x7f5390800dc9 - std[287527946f71f0bc]::sys::backtrace::__rust_end_short_backtrace::<std[287527946f71f0bc]::panicking::panic_handler::{closure#0}, !>
9: 0x7f539080bbdd - __rustc[5ec7081ce87b032f]::rust_begin_unwind
10: 0x7f538d30cfbc - core[7477a31a1a34cc49]::panicking::panic_fmt
11: 0x7f538f17d6d3 - core[7477a31a1a34cc49]::panicking::assert_failed_inner
12: 0x7f5390566dda - core[7477a31a1a34cc49]::panicking::assert_failed::<alloc[979041e9952e771b]::vec::Vec<rustc_type_ir[b93cf349b3a4f34d]::solve::Goal<rustc_middle[725063e074f29df]::ty::context::TyCtxt, rustc_middle[725063e074f29df]::ty::predicate::Predicate>>, alloc[979041e9952e771b]::vec::Vec<rustc_type_ir[b93cf349b3a4f34d]::solve::Goal<rustc_middle[725063e074f29df]::ty::context::TyCtxt, rustc_middle[725063e074f29df]::ty::predicate::Predicate>>>
13: 0x7f5391c39d13 - <rustc_hir_typeck[ed5453188701a25b]::fn_ctxt::FnCtxt>::compute_definition_site_hidden_types
14: 0x7f5391bb837a - rustc_hir_typeck[ed5453188701a25b]::typeck_with_inspect::{closure#0}
15: 0x7f5391bb26b4 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>
16: 0x7f5390f5522a - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
17: 0x7f5390f54b09 - rustc_query_impl[f20b8284200e680a]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
18: 0x7f539145010a - rustc_mir_build[80b6bf0f2af09b99]::thir::pattern::check_match::check_match
19: 0x7f539144f4d1 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::check_match::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>>
20: 0x7f5391592f78 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
21: 0x7f5391592c3d - rustc_query_impl[f20b8284200e680a]::query_impl::check_match::get_query_non_incr::__rust_end_short_backtrace
22: 0x7f5391311667 - rustc_mir_build[80b6bf0f2af09b99]::builder::build_mir_inner_impl
23: 0x7f5390e08dea - rustc_mir_transform[f63ee9052e691c]::mir_built
24: 0x7f5390e08db3 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::mir_built::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>
25: 0x7f5390f5522a - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
26: 0x7f5390f54c89 - rustc_query_impl[f20b8284200e680a]::query_impl::mir_built::get_query_non_incr::__rust_end_short_backtrace
27: 0x7f5390e4eb97 - rustc_mir_transform[f63ee9052e691c]::ffi_unwind_calls::has_ffi_unwind_calls
28: 0x7f5390e4e5a9 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::has_ffi_unwind_calls::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>>
29: 0x7f5391592f78 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
30: 0x7f5391592afd - rustc_query_impl[f20b8284200e680a]::query_impl::has_ffi_unwind_calls::get_query_non_incr::__rust_end_short_backtrace
31: 0x7f5391b26bcd - rustc_mir_transform[f63ee9052e691c]::mir_promoted
32: 0x7f5391b269e0 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::mir_promoted::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 16usize]>>
33: 0x7f53917e9475 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 16usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
34: 0x7f53917e900c - rustc_query_impl[f20b8284200e680a]::query_impl::mir_promoted::get_query_non_incr::__rust_end_short_backtrace
35: 0x7f5391f3d325 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>
36: 0x7f5390f5522a - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
37: 0x7f5390f4bf99 - rustc_query_impl[f20b8284200e680a]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
38: 0x7f5391e143b5 - rustc_hir_analysis[1a80394817eddfdd]::collect::type_of::opaque::find_opaque_ty_constraints_for_rpit
39: 0x7f5391e14042 - rustc_hir_analysis[1a80394817eddfdd]::collect::type_of::type_of_opaque
40: 0x7f5391e13f47 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::type_of_opaque::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>
41: 0x7f5390e173c5 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_query_system[b7e73caa2c2ad9a]::query::caches::DefIdCache<rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
42: 0x7f53917d90db - rustc_query_impl[f20b8284200e680a]::query_impl::type_of_opaque::get_query_non_incr::__rust_end_short_backtrace
43: 0x7f53917bd8b6 - rustc_hir_analysis[1a80394817eddfdd]::collect::type_of::type_of
44: 0x7f5390f75c26 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::type_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>
45: 0x7f5390e173c5 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_query_system[b7e73caa2c2ad9a]::query::caches::DefIdCache<rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
46: 0x7f5390e16f6f - rustc_query_impl[f20b8284200e680a]::query_impl::type_of::get_query_non_incr::__rust_end_short_backtrace
47: 0x7f5391e14abb - rustc_hir_analysis[1a80394817eddfdd]::check::check::check_opaque
48: 0x7f539159b904 - rustc_hir_analysis[1a80394817eddfdd]::check::check::check_item_type
49: 0x7f539159379c - rustc_hir_analysis[1a80394817eddfdd]::check::wfcheck::check_well_formed
50: 0x7f539159376b - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>>
51: 0x7f53915931e3 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_data_structures[e0d8483206daafa2]::vec_cache::VecCache<rustc_span[851f35e07e3c2dd4]::def_id::LocalDefId, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>, rustc_query_system[b7e73caa2c2ad9a]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
52: 0x7f5391592cd6 - rustc_query_impl[f20b8284200e680a]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
53: 0x7f53915904d1 - rustc_hir_analysis[1a80394817eddfdd]::check::wfcheck::check_type_wf
54: 0x7f539159035d - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::check_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>>
55: 0x7f5391fa3e85 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_query_system[b7e73caa2c2ad9a]::query::caches::SingleCache<rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
56: 0x7f5391fa3b36 - rustc_query_impl[f20b8284200e680a]::query_impl::check_type_wf::get_query_non_incr::__rust_end_short_backtrace
57: 0x7f539193f316 - rustc_hir_analysis[1a80394817eddfdd]::check_crate
58: 0x7f5390f493db - rustc_interface[5c48368f5debe80d]::passes::analysis
59: 0x7f5390f49035 - rustc_query_impl[f20b8284200e680a]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[f20b8284200e680a]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 0usize]>>
60: 0x7f5391fa4be3 - rustc_query_system[b7e73caa2c2ad9a]::query::plumbing::try_execute_query::<rustc_query_impl[f20b8284200e680a]::DynamicConfig<rustc_query_system[b7e73caa2c2ad9a]::query::caches::SingleCache<rustc_middle[725063e074f29df]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[f20b8284200e680a]::plumbing::QueryCtxt, false>
61: 0x7f5391fa49ce - rustc_query_impl[f20b8284200e680a]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
62: 0x7f5392182c11 - <rustc_interface[5c48368f5debe80d]::passes::create_and_enter_global_ctxt<core[7477a31a1a34cc49]::option::Option<rustc_interface[5c48368f5debe80d]::queries::Linker>, rustc_driver_impl[517260a07841a630]::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core[7477a31a1a34cc49]::ops::function::FnOnce<(&rustc_session[eb79e6d3104f29ae]::session::Session, rustc_middle[725063e074f29df]::ty::context::CurrentGcx, alloc[979041e9952e771b]::sync::Arc<rustc_data_structures[e0d8483206daafa2]::jobserver::Proxy>, &std[287527946f71f0bc]::sync::once_lock::OnceLock<rustc_middle[725063e074f29df]::ty::context::GlobalCtxt>, &rustc_data_structures[e0d8483206daafa2]::sync::worker_local::WorkerLocal<rustc_middle[725063e074f29df]::arena::Arena>, &rustc_data_structures[e0d8483206daafa2]::sync::worker_local::WorkerLocal<rustc_hir[7eac7792dedc1861]::Arena>, rustc_driver_impl[517260a07841a630]::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
63: 0x7f5391ff5d34 - rustc_interface[5c48368f5debe80d]::interface::run_compiler::<(), rustc_driver_impl[517260a07841a630]::run_compiler::{closure#0}>::{closure#1}
64: 0x7f5391f5aa3a - std[287527946f71f0bc]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[5c48368f5debe80d]::util::run_in_thread_with_globals<rustc_interface[5c48368f5debe80d]::util::run_in_thread_pool_with_globals<rustc_interface[5c48368f5debe80d]::interface::run_compiler<(), rustc_driver_impl[517260a07841a630]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
65: 0x7f5391f5a7fe - <std[287527946f71f0bc]::thread::lifecycle::spawn_unchecked<rustc_interface[5c48368f5debe80d]::util::run_in_thread_with_globals<rustc_interface[5c48368f5debe80d]::util::run_in_thread_pool_with_globals<rustc_interface[5c48368f5debe80d]::interface::run_compiler<(), rustc_driver_impl[517260a07841a630]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[7477a31a1a34cc49]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
66: 0x7f5391f5c5c4 - <std[287527946f71f0bc]::sys::thread::unix::Thread>::new::thread_start
67: 0x7f538b89698b - <unknown>
68: 0x7f538b91a9cc - <unknown>
69: 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: rustc 1.95.0-nightly (621d76794 2026-01-18) running on x86_64-unknown-linux-gnu
note: compiler flags: -Z next-solver=globally -Z dump-mir-dir=dir
query stack during panic:
#0 [typeck] type-checking `Bar::new`
#1 [check_match] match-checking `Bar::new`
#2 [mir_built] building MIR for `Bar::new`
#3 [has_ffi_unwind_calls] checking if `Bar::new` contains FFI-unwind calls
#4 [mir_promoted] promoting constants in MIR for `Bar::new`
#5 [mir_borrowck] borrow-checking `Bar::new`
#6 [type_of_opaque] computing type of opaque `Bar::new::{opaque#0}`
#7 [type_of] computing type of `Bar::new::{opaque#0}`
#8 [check_well_formed] checking that `Bar::new::{opaque#0}` is well-formed
#9 [check_type_wf] checking that types are well-formed
#10 [analysis] running analysis passes on crate `mvce`
end of query stack
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0277, E0308, E0425, E0601, E0658.
For more information about an error, try `rustc --explain E0277`.
@rustbot label +WG-trait-system-refactor