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ICE: `assertion 'left == right' failed` `?1t == T/#0`

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C-bug F-inherent_associated_types I-ICE requires-debug-assertions T-compiler WG-trait-system-refactor
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Rust
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Description

auto-reduced (treereduce-rust):

//@compile-flags: -Znext-solver=globally
#![feature(inherent_associated_types)]

struct D<T> {
    a: T,
}

impl<T: Default> D<T> {
    type Item = T;

    fn next() -> Self::Item {
        Self::Item::default()
    }
}

original:

//@ check-pass

#![feature(inherent_associated_types)]
//~^ WARN the feature `inherent_associated_types` is incomplete

struct D<T> {
  a: T
}

impl<T: Default> D<T> {
    type Item = T;

    fn next() -> Self::Item {
        Self::Item::default()
    }
}


fn main() {
}

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:
https://github.com/rust-lang/rust/blob/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs#L185-L197

Command:
/home/matthias/.rustup/toolchains/alt-master/bin/rustc -Znext-solver=globally

Program output 

warning: the feature `inherent_associated_types` is incomplete and may not be safe to use and/or cause compiler crashes
 --> /tmp/icemaker_global_tempdir.A43Fjzyu80eF/rustc_testrunner_tmpdir_reporting.ft3v4Xoso23V/mvce.rs:1:12
  |
1 | #![feature(inherent_associated_types)]
  |            ^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #8995 <https://github.com/rust-lang/rust/issues/8995> for more information
  = note: `#[warn(incomplete_features)]` on by default

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.A43Fjzyu80eF/rustc_testrunner_tmpdir_reporting.ft3v4Xoso23V/mvce.rs:13:2
   |
13 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.A43Fjzyu80eF/rustc_testrunner_tmpdir_reporting.ft3v4Xoso23V/mvce.rs`


thread 'rustc' (1068749) panicked at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:191:9:
assertion `left == right` failed
  left: ?1t
 right: T/#0
stack backtrace:
   0:     0x7f2da5163bf0 - std[85cd0efd8843bbc4]::backtrace_rs::backtrace::libunwind::trace
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/../../backtrace/src/backtrace/libunwind.rs:117:9
   1:     0x7f2da5163bf0 - std[85cd0efd8843bbc4]::backtrace_rs::backtrace::trace_unsynchronized::<std[85cd0efd8843bbc4]::sys::backtrace::_print_fmt::{closure#1}>
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/../../backtrace/src/backtrace/mod.rs:66:14
   2:     0x7f2da5163bf0 - std[85cd0efd8843bbc4]::sys::backtrace::_print_fmt
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/sys/backtrace.rs:74:9
   3:     0x7f2da5163bf0 - <<std[85cd0efd8843bbc4]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[b384759a19688fa6]::fmt::Display>::fmt
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/sys/backtrace.rs:44:26
   4:     0x7f2da07eb58e - <core[b384759a19688fa6]::fmt::rt::Argument>::fmt
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/fmt/rt.rs:152:76
   5:     0x7f2da07eb58e - core[b384759a19688fa6]::fmt::write
   6:     0x7f2da517c44c - std[85cd0efd8843bbc4]::io::default_write_fmt::<std[85cd0efd8843bbc4]::sys::stdio::unix::Stderr>
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/io/mod.rs:639:11
   7:     0x7f2da517c44c - <std[85cd0efd8843bbc4]::sys::stdio::unix::Stderr as std[85cd0efd8843bbc4]::io::Write>::write_fmt
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/io/mod.rs:1994:13
   8:     0x7f2da5129586 - <std[85cd0efd8843bbc4]::sys::backtrace::BacktraceLock>::print
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/sys/backtrace.rs:47:9
   9:     0x7f2da5129586 - std[85cd0efd8843bbc4]::panicking::default_hook::{closure#0}
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:292:27
  10:     0x7f2da5152e11 - std[85cd0efd8843bbc4]::panicking::default_hook
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:319:9
  11:     0x7f2da1bb8778 - <alloc[f567be85ce8074fa]::boxed::Box<dyn for<'a, 'b> core[b384759a19688fa6]::ops::function::Fn<(&'a std[85cd0efd8843bbc4]::panic::PanicHookInfo<'b>,), Output = ()> + core[b384759a19688fa6]::marker::Send + core[b384759a19688fa6]::marker::Sync> as core[b384759a19688fa6]::ops::function::Fn<(&std[85cd0efd8843bbc4]::panic::PanicHookInfo,)>>::call
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/alloc/src/boxed.rs:2220:9
  12:     0x7f2da1bb8778 - rustc_driver_impl[44972498707c6af1]::install_ice_hook::{closure#1}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_driver_impl/src/lib.rs:1442:17
  13:     0x7f2da1bb8778 - <alloc[f567be85ce8074fa]::boxed::Box<rustc_driver_impl[44972498707c6af1]::install_ice_hook::{closure#1}> as core[b384759a19688fa6]::ops::function::Fn<(&dyn for<'a, 'b> core[b384759a19688fa6]::ops::function::Fn<(&'a std[85cd0efd8843bbc4]::panic::PanicHookInfo<'b>,), Output = ()> + core[b384759a19688fa6]::marker::Send + core[b384759a19688fa6]::marker::Sync, &std[85cd0efd8843bbc4]::panic::PanicHookInfo)>>::call
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/alloc/src/boxed.rs:2220:9
  14:     0x7f2da1bb8778 - std[85cd0efd8843bbc4]::panicking::update_hook::<alloc[f567be85ce8074fa]::boxed::Box<rustc_driver_impl[44972498707c6af1]::install_ice_hook::{closure#1}>>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:235:47
  15:     0x7f2da515318a - <alloc[f567be85ce8074fa]::boxed::Box<dyn for<'a, 'b> core[b384759a19688fa6]::ops::function::Fn<(&'a std[85cd0efd8843bbc4]::panic::PanicHookInfo<'b>,), Output = ()> + core[b384759a19688fa6]::marker::Send + core[b384759a19688fa6]::marker::Sync> as core[b384759a19688fa6]::ops::function::Fn<(&std[85cd0efd8843bbc4]::panic::PanicHookInfo,)>>::call
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/alloc/src/boxed.rs:2220:9
  16:     0x7f2da515318a - std[85cd0efd8843bbc4]::panicking::panic_with_hook
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:833:13
  17:     0x7f2da512964a - std[85cd0efd8843bbc4]::panicking::panic_handler::{closure#0}
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:698:13
  18:     0x7f2da5114c29 - std[85cd0efd8843bbc4]::sys::backtrace::__rust_end_short_backtrace::<std[85cd0efd8843bbc4]::panicking::panic_handler::{closure#0}, !>
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/sys/backtrace.rs:182:18
  19:     0x7f2da512b6ad - __rustc[5ec7081ce87b032f]::rust_begin_unwind
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:689:5
  20:     0x7f2da07ebfbc - core[b384759a19688fa6]::panicking::panic_fmt
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/panicking.rs:80:14
  21:     0x7f2da07ebe43 - core[b384759a19688fa6]::panicking::assert_failed_inner
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/panicking.rs:439:17
  22:     0x7f2da30ba846 - core[b384759a19688fa6]::panicking::assert_failed::<rustc_middle[95d44b15229f0c75]::ty::Ty, rustc_middle[95d44b15229f0c75]::ty::Ty>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/panicking.rs:394:5
  23:     0x7f2da4d5686c - <rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError> as rustc_type_ir[6f10e774b3df356f]::fold::FallibleTypeFolder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_ty::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:191:9
  24:     0x7f2da4d5686c - <rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError> as rustc_type_ir[6f10e774b3df356f]::fold::FallibleTypeFolder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_ty
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:188:5
  25:     0x7f2da4a2bf26 - <rustc_middle[95d44b15229f0c75]::ty::Ty as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/structural_impls.rs:359:16
  26:     0x7f2da4a2bf26 - <rustc_middle[95d44b15229f0c75]::ty::generic_args::GenericArg as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/generic_args.rs:336:44
  27:     0x7f2da4a2ec90 - <&rustc_middle[95d44b15229f0c75]::ty::list::RawList<(), rustc_middle[95d44b15229f0c75]::ty::generic_args::GenericArg> as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/generic_args.rs:614:38
  28:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::predicate::TraitRef<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt> as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/predicate.rs:57:55
  29:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::predicate::TraitPredicate<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt> as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/predicate.rs:134:55
  30:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::predicate_kind::ClauseKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt> as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/predicate_kind.rs:13:55
  31:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt> as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/predicate_kind.rs:61:55
  32:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::binder::Binder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt, rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>> as rustc_type_ir[6f10e774b3df356f]::fold::TypeSuperFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/binder.rs:140:34
  33:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::binder::Binder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt, rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>>::try_map_bound::<<rustc_type_ir[6f10e774b3df356f]::binder::Binder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt, rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>> as rustc_type_ir[6f10e774b3df356f]::fold::TypeSuperFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_super_fold_with<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>::{closure#0}, rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>, alloc[f567be85ce8074fa]::vec::Vec<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/binder.rs:212:21
  34:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::binder::Binder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt, rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>> as rustc_type_ir[6f10e774b3df356f]::fold::TypeSuperFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/binder.rs:140:14
  35:     0x7f2da49b0c07 - <rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError> as rustc_type_ir[6f10e774b3df356f]::fold::FallibleTypeFolder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_binder::<rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:183:19
  36:     0x7f2da49b0c07 - <rustc_type_ir[6f10e774b3df356f]::binder::Binder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt, rustc_type_ir[6f10e774b3df356f]::predicate_kind::PredicateKind<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>> as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/binder.rs:121:16
  37:     0x7f2da49b0c07 - <rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate as rustc_type_ir[6f10e774b3df356f]::fold::TypeSuperFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_super_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/structural_impls.rs:595:31
  38:     0x7f2da49b0c07 - <rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError> as rustc_type_ir[6f10e774b3df356f]::fold::FallibleTypeFolder<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_predicate
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_type_ir/src/fold.rs:195:11
  39:     0x7f2da49b0c07 - <rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate as rustc_type_ir[6f10e774b3df356f]::fold::TypeFoldable<rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>>::try_fold_with::<rustc_trait_selection[13e39609c7dac538]::solve::normalize::NormalizationFolder<rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/structural_impls.rs:537:16
  40:     0x7f2da49b0c07 - rustc_trait_selection[13e39609c7dac538]::solve::normalize::deeply_normalize_with_skipped_universes_and_ambiguous_coroutine_goals::<rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate, rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:81:23
  41:     0x7f2da49b0c07 - rustc_trait_selection[13e39609c7dac538]::solve::normalize::deeply_normalize_with_skipped_universes::<rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate, rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:47:9
  42:     0x7f2da49b0c07 - rustc_trait_selection[13e39609c7dac538]::solve::normalize::deeply_normalize::<rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate, rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/solve/normalize.rs:28:5
  43:     0x7f2da4c827fc - <rustc_infer[4ff9c416af65d166]::infer::at::At as rustc_trait_selection[13e39609c7dac538]::traits::normalize::NormalizeExt>::deeply_normalize::<rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate, rustc_infer[4ff9c416af65d166]::traits::engine::ScrubbedTraitError>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/normalize.rs:63:13
  44:     0x7f2da4c827fc - <rustc_trait_selection[13e39609c7dac538]::traits::engine::ObligationCtxt>::deeply_normalize::<rustc_middle[95d44b15229f0c75]::ty::predicate::Predicate>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/engine.rs:351:41
  45:     0x7f2da4c827fc - rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::implied_outlives_bounds::compute_implied_outlives_bounds_inner
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs:96:18
  46:     0x7f2da11807c4 - <rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds as rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::QueryTypeOp>::perform_locally_with_next_solver
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs:47:9
  47:     0x7f2da11807c4 - <rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds> as rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::TypeOp>::fully_perform::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs:161:23
  48:     0x7f2da11807c4 - rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::custom::scrape_region_constraints::<rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds>, alloc[f567be85ce8074fa]::vec::Vec<rustc_middle[95d44b15229f0c75]::traits::query::OutlivesBound>, <rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds> as rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::TypeOp>::fully_perform::{closure#0}>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:94:21
  49:     0x7f2da11807c4 - <rustc_infer[4ff9c416af65d166]::infer::InferCtxt>::commit_if_ok::<alloc[f567be85ce8074fa]::vec::Vec<rustc_middle[95d44b15229f0c75]::traits::query::OutlivesBound>, rustc_span[48a97fb2068e7f97]::ErrorGuaranteed, rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::custom::scrape_region_constraints<rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds>, alloc[f567be85ce8074fa]::vec::Vec<rustc_middle[95d44b15229f0c75]::traits::query::OutlivesBound>, <rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds> as rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::TypeOp>::fully_perform::{closure#0}>::{closure#0}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_infer/src/infer/snapshot/mod.rs:86:17
  50:     0x7f2da11807c4 - rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::custom::scrape_region_constraints::<rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds>, alloc[f567be85ce8074fa]::vec::Vec<rustc_middle[95d44b15229f0c75]::traits::query::OutlivesBound>, <rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds> as rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::TypeOp>::fully_perform::{closure#0}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs:92:23
  51:     0x7f2da11807c4 - <rustc_middle[95d44b15229f0c75]::ty::ParamEnvAnd<rustc_middle[95d44b15229f0c75]::traits::query::type_op::ImpliedOutlivesBounds> as rustc_trait_selection[13e39609c7dac538]::traits::query::type_op::TypeOp>::fully_perform
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs:156:23
  52:     0x7f2da11807c4 - <rustc_borrowck[c71726b702da8474]::type_check::free_region_relations::UniversalRegionRelationsBuilder>::add_implied_bounds
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/type_check/free_region_relations.rs:369:14
  53:     0x7f2da11a26f9 - <rustc_borrowck[c71726b702da8474]::type_check::free_region_relations::UniversalRegionRelationsBuilder>::create
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/type_check/free_region_relations.rs:240:43
  54:     0x7f2da11a26f9 - rustc_borrowck[c71726b702da8474]::type_check::free_region_relations::create
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/type_check/free_region_relations.rs:64:6
  55:     0x7f2da11a26f9 - rustc_borrowck[c71726b702da8474]::type_check::type_check
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/type_check/mod.rs:124:9
  56:     0x7f2da106da86 - rustc_borrowck[c71726b702da8474]::borrowck_collect_region_constraints
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/lib.rs:354:9
  57:     0x7f2da107e197 - <rustc_borrowck[c71726b702da8474]::root_cx::BorrowCheckRootCtxt>::do_mir_borrowck
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/root_cx.rs:253:26
  58:     0x7f2da105a4cf - rustc_borrowck[c71726b702da8474]::mir_borrowck
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_borrowck/src/lib.rs:135:17
  59:     0x7f2da3e93d3e - rustc_query_impl[9b48450d2bbb61ea]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_impl/src/plumbing.rs:282:9
  60:     0x7f2da3e93d3e - rustc_query_impl[9b48450d2bbb61ea]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[9b48450d2bbb61ea]::query_impl::mir_borrowck::dynamic_query::{closure#2}::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_impl/src/plumbing.rs:552:18
  61:     0x7f2da42a101b - rustc_query_impl[9b48450d2bbb61ea]::query_impl::mir_borrowck::dynamic_query::{closure#2}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_impl/src/plumbing.rs:629:25
  62:     0x7f2da42a101b - <rustc_query_impl[9b48450d2bbb61ea]::query_impl::mir_borrowck::dynamic_query::{closure#2} as core[b384759a19688fa6]::ops::function::FnOnce<(rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt, rustc_span[48a97fb2068e7f97]::def_id::LocalDefId)>>::call_once
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/ops/function.rs:250:5
  63:     0x7f2da3fb0fa2 - <rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_data_structures[49d24dc8d9283e5f]::vec_cache::VecCache<rustc_hir_id[71e3564572537a63]::OwnerId, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[8c93b95bb0d37949]::dep_graph::graph::DepNodeIndex>, false, false, false> as rustc_query_system[8c93b95bb0d37949]::query::config::QueryConfig<rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>>::compute
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_impl/src/lib.rs:116:9
  64:     0x7f2da3fb0fa2 - rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr::<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_data_structures[49d24dc8d9283e5f]::vec_cache::VecCache<rustc_hir_id[71e3564572537a63]::OwnerId, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[8c93b95bb0d37949]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_system/src/query/plumbing.rs:497:72
  65:     0x7f2da3fb0fa2 - rustc_middle[95d44b15229f0c75]::ty::context::tls::enter_context::<rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_data_structures[49d24dc8d9283e5f]::vec_cache::VecCache<rustc_hir_id[71e3564572537a63]::OwnerId, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[8c93b95bb0d37949]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context/tls.rs:60:9
  66:     0x7f2da3fb0fa2 - <std[85cd0efd8843bbc4]::thread::local::LocalKey<core[b384759a19688fa6]::cell::Cell<*const ()>>>::try_with::<rustc_middle[95d44b15229f0c75]::ty::context::tls::enter_context<rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_data_structures[49d24dc8d9283e5f]::vec_cache::VecCache<rustc_hir_id[71e3564572537a63]::OwnerId, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>, rustc_query_system[8c93b95bb0d37949]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>>::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 8usize]>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/thread/local.rs:513:12

<snip>



 119:     0x7f2da3f13a4b - rustc_middle[95d44b15229f0c75]::ty::context::tls::with_context::<rustc_middle[95d44b15229f0c75]::ty::context::tls::with_related_context<<rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt as rustc_query_system[8c93b95bb0d37949]::query::QueryContext>::start_query<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>, rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}>::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context/tls.rs:90:5
 120:     0x7f2da3f13a4b - rustc_middle[95d44b15229f0c75]::ty::context::tls::with_related_context::<<rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt as rustc_query_system[8c93b95bb0d37949]::query::QueryContext>::start_query<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>, rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}>::{closure#0}, rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context/tls.rs:103:5
 121:     0x7f2da3f13a4b - <rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt as rustc_query_system[8c93b95bb0d37949]::query::QueryContext>::start_query::<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>, rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_impl/src/plumbing.rs:142:9
 122:     0x7f2da3f13a4b - rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job_non_incr::<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_system/src/query/plumbing.rs:497:22
 123:     0x7f2da3f13a4b - rustc_query_system[8c93b95bb0d37949]::query::plumbing::execute_job::<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt, false>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_system/src/query/plumbing.rs:433:9
 124:     0x7f2da3f13a4b - rustc_query_system[8c93b95bb0d37949]::query::plumbing::try_execute_query::<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt, false>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_system/src/query/plumbing.rs:376:13
 125:     0x7f2da412c8cc - rustc_query_system[8c93b95bb0d37949]::query::plumbing::get_query_non_incr::<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_system/src/query/plumbing.rs:818:32
 126:     0x7f2da412c8cc - stacker[cd2969ced30f4328]::maybe_grow::<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>, rustc_query_system[8c93b95bb0d37949]::query::plumbing::get_query_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}>
                               at /rust/deps/stacker-0.1.21/src/lib.rs:57:9
 127:     0x7f2da412c8cc - rustc_data_structures[49d24dc8d9283e5f]::stack::ensure_sufficient_stack::<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>, rustc_query_system[8c93b95bb0d37949]::query::plumbing::get_query_non_incr<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>::{closure#0}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_data_structures/src/stack.rs:21:5
 128:     0x7f2da412c8cc - rustc_query_system[8c93b95bb0d37949]::query::plumbing::get_query_non_incr::<rustc_query_impl[9b48450d2bbb61ea]::DynamicConfig<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[9b48450d2bbb61ea]::plumbing::QueryCtxt>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_system/src/query/plumbing.rs:818:5
 129:     0x7f2da412c8cc - rustc_query_impl[9b48450d2bbb61ea]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_query_impl/src/plumbing.rs:605:26
 130:     0x7f2da1bc47f6 - rustc_middle[95d44b15229f0c75]::query::inner::query_ensure::<rustc_query_system[8c93b95bb0d37949]::query::caches::SingleCache<rustc_middle[95d44b15229f0c75]::query::erase::Erased<[u8; 0usize]>>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/query/inner.rs:51:9
 131:     0x7f2da1bc47f6 - <rustc_middle[95d44b15229f0c75]::query::plumbing::TyCtxtEnsureOk>::analysis
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/query/plumbing.rs:173:9
 132:     0x7f2da1bc47f6 - rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_driver_impl/src/lib.rs:367:29
 133:     0x7f2da1bc47f6 - rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt::<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/passes.rs:1021:27
 134:     0x7f2da1bc47f6 - <rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>::enter::<rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#1}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context.rs:1648:37
 135:     0x7f2da1bc47f6 - rustc_middle[95d44b15229f0c75]::ty::context::tls::enter_context::<<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>::enter<rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#1}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context/tls.rs:60:9
 136:     0x7f2da1bc47f6 - <std[85cd0efd8843bbc4]::thread::local::LocalKey<core[b384759a19688fa6]::cell::Cell<*const ()>>>::try_with::<rustc_middle[95d44b15229f0c75]::ty::context::tls::enter_context<<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>::enter<rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#1}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/thread/local.rs:513:12
 137:     0x7f2da1bc47f6 - <std[85cd0efd8843bbc4]::thread::local::LocalKey<core[b384759a19688fa6]::cell::Cell<*const ()>>>::with::<rustc_middle[95d44b15229f0c75]::ty::context::tls::enter_context<<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>::enter<rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#1}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/thread/local.rs:477:20
 138:     0x7f2da1bc47f6 - rustc_middle[95d44b15229f0c75]::ty::context::tls::enter_context::<<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>::enter<rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>::{closure#1}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context/tls.rs:57:9
 139:     0x7f2da1bc47f6 - <rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>::enter::<rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}, core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context.rs:1648:9
 140:     0x7f2da1bc47f6 - <rustc_middle[95d44b15229f0c75]::ty::context::TyCtxt>::create_global_ctxt::<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_middle/src/ty/context.rs:1855:13
 141:     0x7f2da1bc47f6 - rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt::<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/passes.rs:988:9
 142:     0x7f2da1bc47f6 - <rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core[b384759a19688fa6]::ops::function::FnOnce<(&rustc_session[f32f30f223bb8d1b]::session::Session, rustc_middle[95d44b15229f0c75]::ty::context::CurrentGcx, alloc[f567be85ce8074fa]::sync::Arc<rustc_data_structures[49d24dc8d9283e5f]::jobserver::Proxy>, &std[85cd0efd8843bbc4]::sync::once_lock::OnceLock<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>, &rustc_data_structures[49d24dc8d9283e5f]::sync::worker_local::WorkerLocal<rustc_middle[95d44b15229f0c75]::arena::Arena>, &rustc_data_structures[49d24dc8d9283e5f]::sync::worker_local::WorkerLocal<rustc_hir[44808572e84f5864]::Arena>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/ops/function.rs:250:5
 143:     0x7f2da1ba05c3 - <alloc[f567be85ce8074fa]::boxed::Box<dyn for<'a> core[b384759a19688fa6]::ops::function::FnOnce<(&'a rustc_session[f32f30f223bb8d1b]::session::Session, rustc_middle[95d44b15229f0c75]::ty::context::CurrentGcx, alloc[f567be85ce8074fa]::sync::Arc<rustc_data_structures[49d24dc8d9283e5f]::jobserver::Proxy>, &'a std[85cd0efd8843bbc4]::sync::once_lock::OnceLock<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt<'a>>, &'a rustc_data_structures[49d24dc8d9283e5f]::sync::worker_local::WorkerLocal<rustc_middle[95d44b15229f0c75]::arena::Arena<'a>>, &'a rustc_data_structures[49d24dc8d9283e5f]::sync::worker_local::WorkerLocal<rustc_hir[44808572e84f5864]::Arena<'a>>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}), Output = core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>>> as core[b384759a19688fa6]::ops::function::FnOnce<(&rustc_session[f32f30f223bb8d1b]::session::Session, rustc_middle[95d44b15229f0c75]::ty::context::CurrentGcx, alloc[f567be85ce8074fa]::sync::Arc<rustc_data_structures[49d24dc8d9283e5f]::jobserver::Proxy>, &std[85cd0efd8843bbc4]::sync::once_lock::OnceLock<rustc_middle[95d44b15229f0c75]::ty::context::GlobalCtxt>, &rustc_data_structures[49d24dc8d9283e5f]::sync::worker_local::WorkerLocal<rustc_middle[95d44b15229f0c75]::arena::Arena>, &rustc_data_structures[49d24dc8d9283e5f]::sync::worker_local::WorkerLocal<rustc_hir[44808572e84f5864]::Arena>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2})>>::call_once
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/alloc/src/boxed.rs:2206:9
 144:     0x7f2da1ba05c3 - rustc_interface[e546d7f872b6e292]::passes::create_and_enter_global_ctxt::<core[b384759a19688fa6]::option::Option<rustc_interface[e546d7f872b6e292]::queries::Linker>, rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}::{closure#2}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/passes.rs:1029:5
 145:     0x7f2da1bbf20d - rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_driver_impl/src/lib.rs:340:22
 146:     0x7f2da1bbf20d - rustc_interface[e546d7f872b6e292]::interface::run_compiler::<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/interface.rs:552:80
 147:     0x7f2da1bbf20d - <core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}::{closure#0}> as core[b384759a19688fa6]::ops::function::FnOnce<()>>::call_once
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/panic/unwind_safe.rs:274:9
 148:     0x7f2da1bbf20d - std[85cd0efd8843bbc4]::panicking::catch_unwind::do_call::<core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}::{closure#0}>, ()>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:581:40
 149:     0x7f2da1bbf20d - std[85cd0efd8843bbc4]::panicking::catch_unwind::<(), core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}::{closure#0}>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:544:19
 150:     0x7f2da1bbf20d - std[85cd0efd8843bbc4]::panic::catch_unwind::<core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}::{closure#0}>, ()>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panic.rs:359:14
 151:     0x7f2da1bbf20d - rustc_interface[e546d7f872b6e292]::interface::run_compiler::<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/interface.rs:552:23
 152:     0x7f2da1ba33a5 - rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals::<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/util.rs:209:17
 153:     0x7f2da1ba33a5 - rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals::<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/util.rs:163:24
 154:     0x7f2da1ba33a5 - <scoped_tls[4ea76b23e8e67eb5]::ScopedKey<rustc_span[48a97fb2068e7f97]::SessionGlobals>>::set::<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}, ()>
                               at /rust/deps/scoped-tls-1.0.1/src/lib.rs:137:9
 155:     0x7f2da1ba33a5 - rustc_span[48a97fb2068e7f97]::create_session_globals_then::<(), rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}::{closure#0}>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_span/src/lib.rs:144:21
 156:     0x7f2da1ba33a5 - rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals::<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/compiler/rustc_interface/src/util.rs:159:17
 157:     0x7f2da1ba33a5 - std[85cd0efd8843bbc4]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/sys/backtrace.rs:166:18
 158:     0x7f2da1bc6c73 - std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked::<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/thread/lifecycle.rs:91:13
 159:     0x7f2da1bc6c73 - <core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}> as core[b384759a19688fa6]::ops::function::FnOnce<()>>::call_once
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/panic/unwind_safe.rs:274:9
 160:     0x7f2da1bc6c73 - std[85cd0efd8843bbc4]::panicking::catch_unwind::do_call::<core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}>, ()>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:581:40
 161:     0x7f2da1bc6c73 - std[85cd0efd8843bbc4]::panicking::catch_unwind::<(), core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}>>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panicking.rs:544:19
 162:     0x7f2da1bc6c73 - std[85cd0efd8843bbc4]::panic::catch_unwind::<core[b384759a19688fa6]::panic::unwind_safe::AssertUnwindSafe<std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}::{closure#0}>, ()>
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/panic.rs:359:14
 163:     0x7f2da1bc6c73 - std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked::<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/thread/lifecycle.rs:89:26
 164:     0x7f2da1bc6c73 - <std[85cd0efd8843bbc4]::thread::lifecycle::spawn_unchecked<rustc_interface[e546d7f872b6e292]::util::run_in_thread_with_globals<rustc_interface[e546d7f872b6e292]::util::run_in_thread_pool_with_globals<rustc_interface[e546d7f872b6e292]::interface::run_compiler<(), rustc_driver_impl[44972498707c6af1]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[b384759a19688fa6]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
                               at /rustc-dev/621d76794c76fc21c0a6151fbc090120e0230a91/library/core/src/ops/function.rs:250:5
 165:     0x7f2da5160a1f - <alloc[f567be85ce8074fa]::boxed::Box<dyn core[b384759a19688fa6]::ops::function::FnOnce<(), Output = ()> + core[b384759a19688fa6]::marker::Send> as core[b384759a19688fa6]::ops::function::FnOnce<()>>::call_once
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/alloc/src/boxed.rs:2206:9
 166:     0x7f2da5160a1f - <std[85cd0efd8843bbc4]::sys::thread::unix::Thread>::new::thread_start
                               at /rustc/621d76794c76fc21c0a6151fbc090120e0230a91/library/std/src/sys/thread/unix.rs:127:17
 167:     0x7f2d9ec9698b - <unknown>
 168:     0x7f2d9ed1a9cc - <unknown>
 169:                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 [mir_borrowck] borrow-checking `<impl at /tmp/icemaker_global_tempdir.A43Fjzyu80eF/rustc_testrunner_tmpdir_reporting.ft3v4Xoso23V/mvce.rs:7:1: 7:22>::next`
#1 [analysis] running analysis passes on crate `mvce`
end of query stack
error: aborting due to 1 previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0601`.

@rustbot label +F-inherent_associated_types +WG-trait-system-refactor

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Research direction

Start by reproducing the reduced variance-computation-requires-equality.rs case with -Znext-solver=globally, then inspect compiler/rustc_trait_selection/src/solve/normalize.rs around lines 185-197. Trace the normalization assertion involving ?1t and T/#0. Done means this input no longer causes rustc to panic, with the resulting compiler behavior covered by an appropriate regression test.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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