ICE: `cannot convert "'a/#4" to a region vid`

[matthiaskrgr]

auto-reduced (treereduce-rust):

#![feature(generic_const_exprs)]
trait MyTrait<T, U: From<T>> {}

impl<'a, 'b, T, U> MyTrait<T> for U {
    async fn foo(
        _: T,
    ) -> (
        &'a U,
        &'static dyn MyTrait<
            [(); {
                |x: &'a u32| x;
                4
            }],
        >,
    ) {
    }
}

original:

trait MyTrait<T, U: From<T>> {
    async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
}

impl<'a, 'b, T, U> MyTrait<T> for U {
    async fn foo(_: T) -> (&'a U, &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]>) {}
}

Version information

rustc 1.83.0-nightly (5a4ee43c3 2024-10-05)
binary: rustc
commit-hash: 5a4ee43c387110736440cecc375cb5aedc441dbc
commit-date: 2024-10-05
host: x86_64-unknown-linux-gnu
release: 1.83.0-nightly
LLVM version: 19.1.0

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcrate-attr=feature(generic_const_exprs)

Program output

error[E0670]: `async fn` is not permitted in Rust 2015
 --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:4:5
  |
4 |     async fn foo(
  |     ^^^^^ to use `async fn`, switch to Rust 2018 or later
  |
  = help: pass `--edition 2021` to `rustc`
  = note: for more on editions, read https://doc.rust-lang.org/edition-guide

error[E0407]: method `foo` is not a member of trait `MyTrait`
  --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:4:5
   |
4  | /     async fn foo(
5  | |         _: T,
6  | |     ) -> (
7  | |         &'a U,
...  |
14 | |     ) {
15 | |     }
   | |_____^ not a member of trait `MyTrait`

warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
 --> <crate attribute>:1:9
  |
1 | feature(generic_const_exprs)
  |         ^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:16:2
   |
16 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs`

error[E0107]: trait takes 2 generic arguments but 1 generic argument was supplied
 --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:3:20
  |
3 | impl<'a, 'b, T, U> MyTrait<T> for U {
  |                    ^^^^^^^ - supplied 1 generic argument
  |                    |
  |                    expected 2 generic arguments
  |
note: trait defined here, with 2 generic parameters: `T`, `U`
 --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:1:7
  |
1 | trait MyTrait<T, U: From<T>> {}
  |       ^^^^^^^ -  -
help: add missing generic argument
  |
3 | impl<'a, 'b, T, U> MyTrait<T, U> for U {
  |                             +++

error[E0107]: trait takes 2 generic arguments but 1 generic argument was supplied
  --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:8:22
   |
8  |           &'static dyn MyTrait<
   |                        ^^^^^^^ expected 2 generic arguments
9  | /             [(); {
10 | |                 |x: &'a u32| x;
11 | |                 4
12 | |             }],
   | |______________- supplied 1 generic argument
   |
note: trait defined here, with 2 generic parameters: `T`, `U`
  --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:1:7
   |
1  | trait MyTrait<T, U: From<T>> {}
   |       ^^^^^^^ -  -
help: add missing generic argument
   |
12 |             }], U,
   |               +++

error: overly complex generic constant
  --> /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:9:18
   |
9  |               [(); {
   |  __________________^
10 | |                 |x: &'a u32| x;
11 | |                 4
12 | |             }],
   | |_____________^ blocks are not supported in generic constants
   |
   = help: consider moving this anonymous constant into a `const` function
   = note: this operation may be supported in the future

error: internal compiler error: compiler/rustc_borrowck/src/universal_regions.rs:907:36: cannot convert `'a/#4` to a region vid

thread 'rustc' panicked at compiler/rustc_borrowck/src/universal_regions.rs:907:36:
Box<dyn Any>
stack backtrace:
   0:     0x7b70b45249fa - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h585b06d402bc00d5
   1:     0x7b70b4c03426 - core::fmt::write::h62d1c51a5a367817
   2:     0x7b70b5e1a651 - std::io::Write::write_fmt::hd7881933ac2a1e16
   3:     0x7b70b4524852 - std::sys::backtrace::BacktraceLock::print::ha0ac5d8e3803f857
   4:     0x7b70b4526d26 - std::panicking::default_hook::{{closure}}::h7a48a96dd6d0b686
   5:     0x7b70b4526b70 - std::panicking::default_hook::h4ad77b5924a748da
   6:     0x7b70b35db8ff - std[f6927571c1bb7893]::panicking::update_hook::<alloc[1b6d6df6cca9b2d3]::boxed::Box<rustc_driver_impl[83de0f0d7a3bbaf8]::install_ice_hook::{closure#0}>>::{closure#0}
   7:     0x7b70b4527438 - std::panicking::rust_panic_with_hook::h15ea114d0f0705b7
   8:     0x7b70b3615451 - std[f6927571c1bb7893]::panicking::begin_panic::<rustc_errors[33bfe5951055d2f3]::ExplicitBug>::{closure#0}
   9:     0x7b70b36084f6 - std[f6927571c1bb7893]::sys::backtrace::__rust_end_short_backtrace::<std[f6927571c1bb7893]::panicking::begin_panic<rustc_errors[33bfe5951055d2f3]::ExplicitBug>::{closure#0}, !>
  10:     0x7b70b36084b3 - std[f6927571c1bb7893]::panicking::begin_panic::<rustc_errors[33bfe5951055d2f3]::ExplicitBug>
  11:     0x7b70b361ece1 - <rustc_errors[33bfe5951055d2f3]::diagnostic::BugAbort as rustc_errors[33bfe5951055d2f3]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x7b70b3c49ca4 - rustc_middle[4aa8808438232afe]::util::bug::opt_span_bug_fmt::<rustc_span[b73f4c38f6b79966]::span_encoding::Span>::{closure#0}
  13:     0x7b70b3c2fb1a - rustc_middle[4aa8808438232afe]::ty::context::tls::with_opt::<rustc_middle[4aa8808438232afe]::util::bug::opt_span_bug_fmt<rustc_span[b73f4c38f6b79966]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  14:     0x7b70b3c2f9ab - rustc_middle[4aa8808438232afe]::ty::context::tls::with_context_opt::<rustc_middle[4aa8808438232afe]::ty::context::tls::with_opt<rustc_middle[4aa8808438232afe]::util::bug::opt_span_bug_fmt<rustc_span[b73f4c38f6b79966]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  15:     0x7b70b11daa80 - rustc_middle[4aa8808438232afe]::util::bug::bug_fmt
  16:     0x7b70b5449263 - <rustc_borrowck[2a33a37890e0dae7]::type_check::TypeChecker>::push_region_constraints
  17:     0x7b70b5960200 - <rustc_borrowck[2a33a37890e0dae7]::type_check::TypeChecker>::ascribe_user_type_skip_wf
  18:     0x7b70b5c950cd - rustc_borrowck[2a33a37890e0dae7]::type_check::type_check
  19:     0x7b70b4cccfdf - rustc_borrowck[2a33a37890e0dae7]::nll::compute_regions
  20:     0x7b70b5be5975 - rustc_borrowck[2a33a37890e0dae7]::do_mir_borrowck
  21:     0x7b70b5bd7b07 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  22:     0x7b70b502373a - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  23:     0x7b70b5023193 - rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  24:     0x7b70b58d6f06 - rustc_middle[4aa8808438232afe]::query::plumbing::query_get_at::<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>>
  25:     0x7b70b58d6f5a - <rustc_borrowck[2a33a37890e0dae7]::type_check::TypeChecker>::prove_closure_bounds
  26:     0x7b70b4df8d5d - <rustc_borrowck[2a33a37890e0dae7]::type_check::TypeChecker>::typeck_mir
  27:     0x7b70b5c93ec4 - rustc_borrowck[2a33a37890e0dae7]::type_check::type_check
  28:     0x7b70b4cccfdf - rustc_borrowck[2a33a37890e0dae7]::nll::compute_regions
  29:     0x7b70b5be5975 - rustc_borrowck[2a33a37890e0dae7]::do_mir_borrowck
  30:     0x7b70b5bd7b07 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  31:     0x7b70b502373a - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  32:     0x7b70b5023193 - rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_borrowck::get_query_non_incr::__rust_end_short_backtrace
  33:     0x7b70b54e4ca8 - rustc_mir_transform[e62bc607d4a6429b]::mir_drops_elaborated_and_const_checked
  34:     0x7b70b54e42d5 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_drops_elaborated_and_const_checked::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  35:     0x7b70b502373a - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  36:     0x7b70b50230e5 - rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_drops_elaborated_and_const_checked::get_query_non_incr::__rust_end_short_backtrace
  37:     0x7b70b4eab0f1 - rustc_mir_transform[e62bc607d4a6429b]::mir_for_ctfe
  38:     0x7b70b4eaaf9b - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_for_ctfe::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  39:     0x7b70b4c2f378 - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefIdCache<rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  40:     0x7b70b527f73d - rustc_query_impl[7b31fe52c1943d23]::query_impl::mir_for_ctfe::get_query_non_incr::__rust_end_short_backtrace
  41:     0x7b70b527f87e - <rustc_const_eval[31692a344d8da780]::interpret::eval_context::InterpCx<rustc_const_eval[31692a344d8da780]::const_eval::machine::CompileTimeMachine>>::load_mir
  42:     0x7b70b26552ad - rustc_const_eval[31692a344d8da780]::const_eval::eval_queries::eval_to_allocation_raw_provider
  43:     0x7b70b528e836 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 24usize]>>
  44:     0x7b70b528e05a - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefaultCache<rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::mir::interpret::GlobalId>, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  45:     0x7b70b528dc2f - rustc_query_impl[7b31fe52c1943d23]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  46:     0x7b70b52a796b - rustc_const_eval[31692a344d8da780]::const_eval::valtrees::eval_to_valtree
  47:     0x7b70b52a777f - <rustc_const_eval[31692a344d8da780]::provide::{closure#0} as core[e1b34d82e9cff2ed]::ops::function::FnOnce<(rustc_middle[4aa8808438232afe]::ty::context::TyCtxt, rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::mir::interpret::GlobalId>)>>::call_once
  48:     0x7b70b52a7736 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::eval_to_valtree::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 24usize]>>
  49:     0x7b70b52a76ef - <rustc_query_impl[7b31fe52c1943d23]::query_impl::eval_to_valtree::dynamic_query::{closure#2} as core[e1b34d82e9cff2ed]::ops::function::FnOnce<(rustc_middle[4aa8808438232afe]::ty::context::TyCtxt, rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::mir::interpret::GlobalId>)>>::call_once
  50:     0x7b70b528e12e - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefaultCache<rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::mir::interpret::GlobalId>, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  51:     0x7b70b528da48 - rustc_query_impl[7b31fe52c1943d23]::query_impl::eval_to_valtree::get_query_non_incr::__rust_end_short_backtrace
  52:     0x7b70b56ffb44 - rustc_middle[4aa8808438232afe]::query::plumbing::query_get_at::<rustc_query_system[af74fb06ba218297]::query::caches::DefaultCache<rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::mir::interpret::GlobalId>, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 24usize]>>>
  53:     0x7b70b56ff5a2 - <rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>::const_eval_global_id_for_typeck
  54:     0x7b70b56fe4be - <rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>::const_eval_resolve_for_typeck
  55:     0x7b70b56fe107 - <rustc_middle[4aa8808438232afe]::ty::consts::Const>::normalize
  56:     0x7b70b56fd999 - <rustc_trait_selection[d03aaefc9e43bec8]::traits::query::normalize::QueryNormalizer as rustc_type_ir[e4a03ddda3530d0c]::fold::FallibleTypeFolder<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_fold_const
  57:     0x7b70b549c80e - <rustc_traits[c2b3970266ec5fb3]::normalize_erasing_regions::provide::{closure#0} as core[e1b34d82e9cff2ed]::ops::function::FnOnce<(rustc_middle[4aa8808438232afe]::ty::context::TyCtxt, rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::ty::generic_args::GenericArg>)>>::call_once
  58:     0x7b70b549b86f - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::try_normalize_generic_arg_after_erasing_regions::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  59:     0x7b70b549af64 - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefaultCache<rustc_middle[4aa8808438232afe]::ty::ParamEnvAnd<rustc_middle[4aa8808438232afe]::ty::generic_args::GenericArg>, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  60:     0x7b70b549aca0 - rustc_query_impl[7b31fe52c1943d23]::query_impl::try_normalize_generic_arg_after_erasing_regions::get_query_non_incr::__rust_end_short_backtrace
  61:     0x7b70b5e00214 - <rustc_middle[4aa8808438232afe]::ty::normalize_erasing_regions::TryNormalizeAfterErasingRegionsFolder as rustc_type_ir[e4a03ddda3530d0c]::fold::FallibleTypeFolder<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_fold_const
  62:     0x7b70b3946f84 - <rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeFolder<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::fold_const
  63:     0x7b70b385a232 - <rustc_middle[4aa8808438232afe]::ty::Ty as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeSuperFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  64:     0x7b70b3853afd - <&rustc_middle[4aa8808438232afe]::ty::list::RawList<(), rustc_middle[4aa8808438232afe]::ty::generic_args::GenericArg> as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  65:     0x7b70b384a6db - <rustc_type_ir[e4a03ddda3530d0c]::predicate::ExistentialPredicate<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt> as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  66:     0x7b70b385a09f - <rustc_middle[4aa8808438232afe]::ty::Ty as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeSuperFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  67:     0x7b70b385a265 - <rustc_middle[4aa8808438232afe]::ty::Ty as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeSuperFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  68:     0x7b70b385798e - <&rustc_middle[4aa8808438232afe]::ty::list::RawList<(), rustc_middle[4aa8808438232afe]::ty::Ty> as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  69:     0x7b70b385a2f3 - <rustc_middle[4aa8808438232afe]::ty::Ty as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeSuperFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  70:     0x7b70b3853805 - <&rustc_middle[4aa8808438232afe]::ty::list::RawList<(), rustc_middle[4aa8808438232afe]::ty::generic_args::GenericArg> as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  71:     0x7b70b385a1cb - <rustc_middle[4aa8808438232afe]::ty::Ty as rustc_type_ir[e4a03ddda3530d0c]::fold::TypeSuperFoldable<rustc_middle[4aa8808438232afe]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_hir_typeck[e4dc2722ad721e99]::writeback::EagerlyNormalizeConsts>
  72:     0x7b70b5755e1c - <rustc_hir_typeck[e4dc2722ad721e99]::writeback::WritebackCx>::visit_node_id
  73:     0x7b70b1861fdf - <rustc_hir_typeck[e4dc2722ad721e99]::writeback::WritebackCx as rustc_hir[8ec93e1cc47b7a03]::intravisit::Visitor>::visit_expr
  74:     0x7b70b574c640 - <rustc_hir_typeck[e4dc2722ad721e99]::fn_ctxt::FnCtxt>::resolve_type_vars_in_body
  75:     0x7b70b4f363df - rustc_hir_typeck[e4dc2722ad721e99]::typeck
  76:     0x7b70b4f351cf - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  77:     0x7b70b502373a - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  78:     0x7b70b502249b - rustc_query_impl[7b31fe52c1943d23]::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
  79:     0x7b70b553763f - rustc_middle[4aa8808438232afe]::query::plumbing::query_get_at::<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>>
  80:     0x7b70b5b479eb - rustc_hir_analysis[2ca7e8779feeb593]::collect::type_of::type_of_opaque
  81:     0x7b70b5b47925 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::type_of_opaque::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  82:     0x7b70b4c2f378 - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefIdCache<rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  83:     0x7b70b5d8ad46 - rustc_query_impl[7b31fe52c1943d23]::query_impl::type_of_opaque::get_query_non_incr::__rust_end_short_backtrace
  84:     0x7b70b5646540 - rustc_middle[4aa8808438232afe]::query::plumbing::query_get_at::<rustc_query_system[af74fb06ba218297]::query::caches::DefIdCache<rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>>
  85:     0x7b70b24f38da - rustc_hir_analysis[2ca7e8779feeb593]::collect::type_of::type_of
  86:     0x7b70b4c30670 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::type_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>
  87:     0x7b70b4c2f378 - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefIdCache<rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  88:     0x7b70b4c2ef31 - rustc_query_impl[7b31fe52c1943d23]::query_impl::type_of::get_query_non_incr::__rust_end_short_backtrace
  89:     0x7b70b5646540 - rustc_middle[4aa8808438232afe]::query::plumbing::query_get_at::<rustc_query_system[af74fb06ba218297]::query::caches::DefIdCache<rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 8usize]>>>
  90:     0x7b70b5b51c80 - rustc_hir_analysis[2ca7e8779feeb593]::check::check::check_item_type
  91:     0x7b70b2533af6 - rustc_hir_analysis[2ca7e8779feeb593]::check::wfcheck::check_well_formed
  92:     0x7b70b570902b - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>
  93:     0x7b70b5708791 - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  94:     0x7b70b5708410 - rustc_query_impl[7b31fe52c1943d23]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  95:     0x7b70b57090bd - rustc_middle[4aa8808438232afe]::query::plumbing::query_ensure_error_guaranteed::<rustc_query_system[af74fb06ba218297]::query::caches::VecCache<rustc_span[b73f4c38f6b79966]::def_id::LocalDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>, ()>
  96:     0x7b70b570969d - rustc_hir_analysis[2ca7e8779feeb593]::check::wfcheck::check_mod_type_wf
  97:     0x7b70b57090e5 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::check_mod_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>
  98:     0x7b70b570297b - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::DefaultCache<rustc_span[b73f4c38f6b79966]::def_id::LocalModDefId, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
  99:     0x7b70b570272d - rustc_query_impl[7b31fe52c1943d23]::query_impl::check_mod_type_wf::get_query_non_incr::__rust_end_short_backtrace
 100:     0x7b70b501fd3b - rustc_hir_analysis[2ca7e8779feeb593]::check_crate
 101:     0x7b70b501ca97 - rustc_interface[a7beddea6b2aa80d]::passes::run_required_analyses
 102:     0x7b70b59f6f9e - rustc_interface[a7beddea6b2aa80d]::passes::analysis
 103:     0x7b70b59f6f71 - rustc_query_impl[7b31fe52c1943d23]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7b31fe52c1943d23]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>
 104:     0x7b70b5ad31ee - rustc_query_system[af74fb06ba218297]::query::plumbing::try_execute_query::<rustc_query_impl[7b31fe52c1943d23]::DynamicConfig<rustc_query_system[af74fb06ba218297]::query::caches::SingleCache<rustc_middle[4aa8808438232afe]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[7b31fe52c1943d23]::plumbing::QueryCtxt, false>
 105:     0x7b70b5ad2ecf - rustc_query_impl[7b31fe52c1943d23]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
 106:     0x7b70b592151e - rustc_interface[a7beddea6b2aa80d]::interface::run_compiler::<core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>, rustc_driver_impl[83de0f0d7a3bbaf8]::run_compiler::{closure#0}>::{closure#1}
 107:     0x7b70b59d9150 - std[f6927571c1bb7893]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[a7beddea6b2aa80d]::util::run_in_thread_with_globals<rustc_interface[a7beddea6b2aa80d]::util::run_in_thread_pool_with_globals<rustc_interface[a7beddea6b2aa80d]::interface::run_compiler<core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>, rustc_driver_impl[83de0f0d7a3bbaf8]::run_compiler::{closure#0}>::{closure#1}, core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>>::{closure#0}, core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>>
 108:     0x7b70b59d9817 - <<std[f6927571c1bb7893]::thread::Builder>::spawn_unchecked_<rustc_interface[a7beddea6b2aa80d]::util::run_in_thread_with_globals<rustc_interface[a7beddea6b2aa80d]::util::run_in_thread_pool_with_globals<rustc_interface[a7beddea6b2aa80d]::interface::run_compiler<core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>, rustc_driver_impl[83de0f0d7a3bbaf8]::run_compiler::{closure#0}>::{closure#1}, core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>>::{closure#0}, core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[e1b34d82e9cff2ed]::result::Result<(), rustc_span[b73f4c38f6b79966]::ErrorGuaranteed>>::{closure#1} as core[e1b34d82e9cff2ed]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
 109:     0x7b70b59da701 - std::sys::pal::unix::thread::Thread::new::thread_start::h4498a525a6fc6a9e
 110:     0x7b70b70ec39d - <unknown>
 111:     0x7b70b717149c - <unknown>
 112:                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: rustc 1.83.0-nightly (5a4ee43c3 2024-10-05) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z crate-attr=feature(generic_const_exprs) -Z dump-mir-dir=dir

query stack during panic:
#0 [mir_borrowck] borrow-checking `<impl at /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:3:1: 3:36>::foo::{opaque#0}::{constant#0}::{closure#0}`
#1 [mir_borrowck] borrow-checking `<impl at /tmp/icemaker_global_tempdir.eYWrWaRW6iTh/rustc_testrunner_tmpdir_reporting.zSc9AlIqfGJ5/mvce.rs:3:1: 3:36>::foo::{opaque#0}::{constant#0}`
end of query stack
error: aborting due to 7 previous errors; 1 warning emitted

Some errors have detailed explanations: E0107, E0407, E0601, E0670.
For more information about an error, try `rustc --explain E0107`.

@rustbot label +F-generic_const_exprs

[cyrgani]

Reduced:

#![feature(generic_const_exprs)]

async fn foo<'a>() -> [(); {
       let _y: &'a ();
       4
   }] {
}

@rustbot label:+S-has-mcve

[matthiaskrgr]

this bisects to #129244 cc @cjgillot

[matthiaskrgr]

I suspect that this one is the same cause, but does not need GCE:

impl<'a> Alias<'a> {
    async fn take_Box_Box_Alias<'a>(self: Box<Box<u32>>, f: &u32) -> &u32 {
        f
    }
}

[cyrgani]

Reduction of the second example:

impl<'a> Alias {
    async fn f<'a>() {}
}