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ICE: unhandled node Crate(Mod #144888

Closed
#157131
Closed
ICE: unhandled node Crate(Mod#144888
#157131
Labels
C-bugCategory: This is a bug.E-needs-testCall for participation: An issue has been fixed and does not reproduce, but no test has been added.I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️S-has-mcveStatus: A Minimal Complete and Verifiable Example has been found for this issueT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
@matthiaskrgr

Description

@matthiaskrgr
matthiaskrgr
opened on Aug 4, 2025

auto-reduced (treereduce-rust):

struct ActuallySuper;

trait Super<Q> {
    type Assoc;
}

trait Dyn {}
impl<T, U> Dyn for dyn Foo<T, U> + '_ {}

trait Foo<T, U>: Super<ActuallySuper, Assoc = T>
where
    <Self as Mirror>::Assoc: Super,
{
    fn transmute(&self, t: T) -> <Self as Super>::Assoc;
}

trait Mirror {
    type Assoc: ?Sized;
}
impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
original code

original:

use core::marker::PhantomData;

fn transmute<T, U>(t: T) -> U {
    (&PhantomData::<T> as &dyn Foo<T, U>).transmute(t)
}

struct ActuallySuper;
struct NotActuallySuper;
trait Super<Q> {
    type Assoc;
}

trait Dyn {
    type Out;
}
impl<T, U> Dyn for dyn Foo<T, U> + '_ {
    type Out = U;
}
impl<S: Dyn<Out = U> + ?Sized, U> Super<NotActuallySuper> for S {
    type Assoc = U;
}

trait Foo<T, U>: Super<ActuallySuper, Assoc = T> where <Self as Mirror>::Assoc: Super<NotActuallySuper> {
    fn transmute(&self, t: T) -> <Self as Super<NotActuallySuper>>::Assoc;
}

trait Mirror {
    type Assoc: ?Sized;
}
impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {
    type Assoc = T;
}

impl<T, U> Foo<T, U> for PhantomData<T> {
    fn transmute(&self, t: T) -> T {
        t
    }
}
impl<T> Super<ActuallySuper> for PhantomData<T> {
    type Assoc = T;
}
impl<T> Super<NotActuallySuper> for PhantomData<T> {
    type Assoc = T;
}

fn main() {
    let x = String::from("hello, world");
    let s = transmute::<&str, &'static str>(x.as_str());
    drop(x);
    println!("> {s}");
}

Version information

rustc 1.91.0-nightly (f34ba774c 2025-08-03)
binary: rustc
commit-hash: f34ba774c78ea32b7c40598b8ad23e75cdac42a6
commit-date: 2025-08-03
host: x86_64-unknown-linux-gnu
release: 1.91.0-nightly
LLVM version: 20.1.8

Possibly related line of code:

rust/compiler/rustc_hir_analysis/src/collect/generics_of.rs

Lines 220 to 232 in f34ba77

Node::Synthetic => span_bug!(
tcx.def_span(def_id),
"synthetic HIR should have its `generics_of` explicitly fed"
),
_ => span_bug!(tcx.def_span(def_id), "unhandled node {node:?}"),
};
enum Defaults {
Allowed,
// See #36887
FutureCompatDisallowed,

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc

Program output 

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:20:57
   |
20 | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   |                                                         ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs`

error[E0107]: missing generics for trait `Super`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:12:30
   |
12 |     <Self as Mirror>::Assoc: Super,
   |                              ^^^^^ expected 1 generic argument
   |
note: trait defined here, with 1 generic parameter: `Q`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:3:7
   |
 3 | trait Super<Q> {
   |       ^^^^^ -
help: add missing generic argument
   |
12 |     <Self as Mirror>::Assoc: Super<Q>,
   |                                   +++

error[E0107]: missing generics for trait `Super`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:14:43
   |
14 |     fn transmute(&self, t: T) -> <Self as Super>::Assoc;
   |                                           ^^^^^ expected 1 generic argument
   |
note: trait defined here, with 1 generic parameter: `Q`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:3:7
   |
 3 | trait Super<Q> {
   |       ^^^^^ -
help: add missing generic argument
   |
14 |     fn transmute(&self, t: T) -> <Self as Super<Q>>::Assoc;
   |                                                +++

error: internal compiler error: compiler/rustc_hir_analysis/src/collect/generics_of.rs:226:14: unhandled node Crate(Mod { spans: ModSpans { inner_span: /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:1:1: 20:57 (#0), inject_use_span: no-location (#0) }, item_ids: [ItemId { owner_id: DefId(0:1 ~ mvce[718f]::std) }, ItemId { owner_id: DefId(0:2 ~ mvce[718f]::{use#0}) }, ItemId { owner_id: DefId(0:3 ~ mvce[718f]::ActuallySuper) }, ItemId { owner_id: DefId(0:5 ~ mvce[718f]::Super) }, ItemId { owner_id: DefId(0:8 ~ mvce[718f]::Dyn) }, ItemId { owner_id: DefId(0:9 ~ mvce[718f]::{impl#0}) }, ItemId { owner_id: DefId(0:12 ~ mvce[718f]::Foo) }, ItemId { owner_id: DefId(0:16 ~ mvce[718f]::Mirror) }, ItemId { owner_id: DefId(0:18 ~ mvce[718f]::{impl#1}) }] })
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:1:1
   |
 1 | / struct ActuallySuper;
 2 | |
 3 | | trait Super<Q> {
 4 | |     type Assoc;
...  |
20 | | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   | |________________________________________________________^


thread 'rustc' panicked at compiler/rustc_hir_analysis/src/collect/generics_of.rs:226:14:
Box<dyn Any>
stack backtrace:
   0:     0x7effbd80a223 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::he94d81f4cc76bf03
   1:     0x7effbe002d77 - core::fmt::write::h255510a3ffb8d55d
   2:     0x7effbd7ffe03 - std::io::Write::write_fmt::hf8ded1300f0b71a8
   3:     0x7effbd80a082 - std::sys::backtrace::BacktraceLock::print::h3bdc2b992c7e0515
   4:     0x7effbd80db27 - std::panicking::default_hook::{{closure}}::h876682ce5f8046c9
   5:     0x7effbd80d68b - std::panicking::default_hook::h708aafadea70e31d
   6:     0x7effbc87eac3 - std[a2e6032cce42d97f]::panicking::update_hook::<alloc[ff7d08515ebedc7]::boxed::Box<rustc_driver_impl[de6ab808e8043f3f]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x7effbd80e36e - std::panicking::rust_panic_with_hook::hbc7edc3b462870f0
   8:     0x7effbc8b7f91 - std[a2e6032cce42d97f]::panicking::begin_panic::<rustc_errors[3211728c3614e99e]::ExplicitBug>::{closure#0}
   9:     0x7effbc8acf26 - std[a2e6032cce42d97f]::sys::backtrace::__rust_end_short_backtrace::<std[a2e6032cce42d97f]::panicking::begin_panic<rustc_errors[3211728c3614e99e]::ExplicitBug>::{closure#0}, !>
  10:     0x7effbc8acdb7 - std[a2e6032cce42d97f]::panicking::begin_panic::<rustc_errors[3211728c3614e99e]::ExplicitBug>
  11:     0x7effbc8c1c31 - <rustc_errors[3211728c3614e99e]::diagnostic::BugAbort as rustc_errors[3211728c3614e99e]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x7effbce3bb6c - <rustc_errors[3211728c3614e99e]::DiagCtxtHandle>::span_bug::<rustc_span[91be5049b842f401]::span_encoding::Span, alloc[ff7d08515ebedc7]::string::String>
  13:     0x7effbced0757 - rustc_middle[e3248139c571040]::util::bug::opt_span_bug_fmt::<rustc_span[91be5049b842f401]::span_encoding::Span>::{closure#0}
  14:     0x7effbceafefa - rustc_middle[e3248139c571040]::ty::context::tls::with_opt::<rustc_middle[e3248139c571040]::util::bug::opt_span_bug_fmt<rustc_span[91be5049b842f401]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  15:     0x7effbceafd6b - rustc_middle[e3248139c571040]::ty::context::tls::with_context_opt::<rustc_middle[e3248139c571040]::ty::context::tls::with_opt<rustc_middle[e3248139c571040]::util::bug::opt_span_bug_fmt<rustc_span[91be5049b842f401]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  16:     0x7effbad16ac7 - rustc_middle[e3248139c571040]::util::bug::span_bug_fmt::<rustc_span[91be5049b842f401]::span_encoding::Span>
  17:     0x7effbaff39f0 - rustc_hir_analysis[7c52b57a28bd59dd]::collect::generics_of::generics_of
  18:     0x7effbe017de9 - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::generics_of::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 8usize]>>
  19:     0x7effbe0184e5 - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_query_system[7e37a266f75ec588]::query::caches::DefIdCache<rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  20:     0x7effbe01821d - rustc_query_impl[3fd9c6a4ad24362]::query_impl::generics_of::get_query_non_incr::__rust_end_short_backtrace
  21:     0x7effbd5e3b7e - <rustc_trait_selection[2c4c2ad9bb59d34]::error_reporting::TypeErrCtxt>::note_and_explain_type_err
  22:     0x7effbc1a16c8 - <rustc_trait_selection[2c4c2ad9bb59d34]::error_reporting::TypeErrCtxt>::note_type_err
  23:     0x7effbd68689e - <rustc_trait_selection[2c4c2ad9bb59d34]::error_reporting::TypeErrCtxt>::report_fulfillment_errors
  24:     0x7effbeae7213 - rustc_trait_selection[2c4c2ad9bb59d34]::traits::do_normalize_predicates
  25:     0x7effbe83eba5 - rustc_trait_selection[2c4c2ad9bb59d34]::traits::normalize_param_env_or_error
  26:     0x7effbe82545f - rustc_trait_selection[2c4c2ad9bb59d34]::traits::dyn_compatibility::virtual_call_violations_for_method
  27:     0x7effbf07ce9a - rustc_trait_selection[2c4c2ad9bb59d34]::traits::dyn_compatibility::dyn_compatibility_violations_for_assoc_item
  28:     0x7effbf07cb2e - <core[606ee596359a9bc5]::iter::adapters::flatten::FlatMap<core[606ee596359a9bc5]::iter::adapters::map::Map<core[606ee596359a9bc5]::iter::adapters::map::Map<core[606ee596359a9bc5]::slice::iter::Iter<(core[606ee596359a9bc5]::option::Option<rustc_span[91be5049b842f401]::symbol::Symbol>, rustc_middle[e3248139c571040]::ty::assoc::AssocItem)>, <rustc_data_structures[a57f2e4fad990afb]::sorted_map::index_map::SortedIndexMultiMap<u32, core[606ee596359a9bc5]::option::Option<rustc_span[91be5049b842f401]::symbol::Symbol>, rustc_middle[e3248139c571040]::ty::assoc::AssocItem>>::iter::{closure#0}>, <rustc_middle[e3248139c571040]::ty::assoc::AssocItems>::in_definition_order::{closure#0}>, alloc[ff7d08515ebedc7]::vec::Vec<rustc_middle[e3248139c571040]::traits::DynCompatibilityViolation>, rustc_trait_selection[2c4c2ad9bb59d34]::traits::dyn_compatibility::dyn_compatibility_violations_for_trait::{closure#0}::{closure#0}> as core[606ee596359a9bc5]::iter::traits::iterator::Iterator>::next
  29:     0x7effbf07b105 - <core[606ee596359a9bc5]::iter::adapters::GenericShunt<core[606ee596359a9bc5]::iter::adapters::map::Map<core[606ee596359a9bc5]::iter::adapters::flatten::FlatMap<core[606ee596359a9bc5]::iter::sources::from_fn::FromFn<rustc_type_ir[d433dbb56c274b65]::elaborate::supertrait_def_ids<rustc_middle[e3248139c571040]::ty::context::TyCtxt>::{closure#0}>, alloc[ff7d08515ebedc7]::vec::Vec<rustc_middle[e3248139c571040]::traits::DynCompatibilityViolation>, rustc_trait_selection[2c4c2ad9bb59d34]::traits::dyn_compatibility::dyn_compatibility_violations::{closure#0}>, core[606ee596359a9bc5]::result::Result<rustc_middle[e3248139c571040]::traits::DynCompatibilityViolation, !>::Ok>, core[606ee596359a9bc5]::result::Result<core[606ee596359a9bc5]::convert::Infallible, !>> as core[606ee596359a9bc5]::iter::traits::iterator::Iterator>::next
  30:     0x7effbf07a47d - rustc_trait_selection[2c4c2ad9bb59d34]::traits::dyn_compatibility::dyn_compatibility_violations
  31:     0x7effbf07a370 - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::dyn_compatibility_violations::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 16usize]>>
  32:     0x7effbf07a357 - <rustc_query_impl[3fd9c6a4ad24362]::query_impl::dyn_compatibility_violations::dynamic_query::{closure#2} as core[606ee596359a9bc5]::ops::function::FnOnce<(rustc_middle[e3248139c571040]::ty::context::TyCtxt, rustc_span[91be5049b842f401]::def_id::DefId)>>::call_once
  33:     0x7effbe19493b - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_query_system[7e37a266f75ec588]::query::caches::DefIdCache<rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  34:     0x7effbf08dfec - rustc_query_impl[3fd9c6a4ad24362]::query_impl::dyn_compatibility_violations::get_query_non_incr::__rust_end_short_backtrace
  35:     0x7effbf08e0b8 - rustc_trait_selection[2c4c2ad9bb59d34]::traits::dyn_compatibility::is_dyn_compatible
  36:     0x7effbf08e021 - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::is_dyn_compatible::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>
  37:     0x7effbe72f950 - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_query_system[7e37a266f75ec588]::query::caches::DefIdCache<rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  38:     0x7effbe732658 - rustc_query_impl[3fd9c6a4ad24362]::query_impl::is_dyn_compatible::get_query_non_incr::__rust_end_short_backtrace
  39:     0x7effbe1f6df9 - rustc_hir_analysis[7c52b57a28bd59dd]::coherence::coherent_trait
  40:     0x7effbe1f5e0b - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::coherent_trait::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>
  41:     0x7effbe72f950 - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_query_system[7e37a266f75ec588]::query::caches::DefIdCache<rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  42:     0x7effbe72e724 - rustc_query_impl[3fd9c6a4ad24362]::query_impl::coherent_trait::get_query_non_incr::__rust_end_short_backtrace
  43:     0x7effbe9162ed - rustc_hir_analysis[7c52b57a28bd59dd]::check::check::check_item_type
  44:     0x7effbe90ff1b - rustc_hir_analysis[7c52b57a28bd59dd]::check::wfcheck::check_well_formed
  45:     0x7effbe90fefd - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::check_well_formed::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>
  46:     0x7effbe90f732 - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_data_structures[a57f2e4fad990afb]::vec_cache::VecCache<rustc_span[91be5049b842f401]::def_id::LocalDefId, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>, rustc_query_system[7e37a266f75ec588]::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  47:     0x7effbe90f256 - rustc_query_impl[3fd9c6a4ad24362]::query_impl::check_well_formed::get_query_non_incr::__rust_end_short_backtrace
  48:     0x7effbe90bf23 - rustc_hir_analysis[7c52b57a28bd59dd]::check::wfcheck::check_type_wf
  49:     0x7effbe90be1d - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::check_type_wf::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>
  50:     0x7effbf10ac7c - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_query_system[7e37a266f75ec588]::query::caches::SingleCache<rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  51:     0x7effbf10aa76 - rustc_query_impl[3fd9c6a4ad24362]::query_impl::check_type_wf::get_query_non_incr::__rust_end_short_backtrace
  52:     0x7effbe580639 - rustc_hir_analysis[7c52b57a28bd59dd]::check_crate
  53:     0x7effbe585384 - rustc_interface[373d4675362b8f62]::passes::analysis
  54:     0x7effbe585047 - rustc_query_impl[3fd9c6a4ad24362]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[3fd9c6a4ad24362]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 0usize]>>
  55:     0x7effbf10b9c8 - rustc_query_system[7e37a266f75ec588]::query::plumbing::try_execute_query::<rustc_query_impl[3fd9c6a4ad24362]::DynamicConfig<rustc_query_system[7e37a266f75ec588]::query::caches::SingleCache<rustc_middle[e3248139c571040]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[3fd9c6a4ad24362]::plumbing::QueryCtxt, false>
  56:     0x7effbf10b636 - rustc_query_impl[3fd9c6a4ad24362]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  57:     0x7effbf36724b - rustc_interface[373d4675362b8f62]::passes::create_and_enter_global_ctxt::<core[606ee596359a9bc5]::option::Option<rustc_interface[373d4675362b8f62]::queries::Linker>, rustc_driver_impl[de6ab808e8043f3f]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  58:     0x7effbf356e71 - rustc_interface[373d4675362b8f62]::interface::run_compiler::<(), rustc_driver_impl[de6ab808e8043f3f]::run_compiler::{closure#0}>::{closure#1}
  59:     0x7effbf1b3241 - std[a2e6032cce42d97f]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[373d4675362b8f62]::util::run_in_thread_with_globals<rustc_interface[373d4675362b8f62]::util::run_in_thread_pool_with_globals<rustc_interface[373d4675362b8f62]::interface::run_compiler<(), rustc_driver_impl[de6ab808e8043f3f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  60:     0x7effbf1b2f22 - <<std[a2e6032cce42d97f]::thread::Builder>::spawn_unchecked_<rustc_interface[373d4675362b8f62]::util::run_in_thread_with_globals<rustc_interface[373d4675362b8f62]::util::run_in_thread_pool_with_globals<rustc_interface[373d4675362b8f62]::interface::run_compiler<(), rustc_driver_impl[de6ab808e8043f3f]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[606ee596359a9bc5]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  61:     0x7effbf1b9085 - std::sys::pal::unix::thread::Thread::new::thread_start::hf6a510012528f331
  62:     0x7effb8aa57eb - <unknown>
  63:     0x7effb8b2918c - <unknown>
  64:                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 1.91.0-nightly (f34ba774c 2025-08-03) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [generics_of] computing generics of ``
#1 [dyn_compatibility_violations] determining dyn-compatibility of trait `Foo`
#2 [is_dyn_compatible] checking if trait `Foo` is dyn-compatible
#3 [coherent_trait] coherence checking all impls of trait `Dyn`
#4 [check_well_formed] checking that `<impl at /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:8:1: 8:38>` is well-formed
#5 [check_type_wf] checking that types are well-formed
#6 [analysis] running analysis passes on this crate
end of query stack
error[E0271]: type mismatch resolving `<Self as Super<ActuallySuper>>::Assoc == Self`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:10:1
   |
10 | trait Foo<T, U>: Super<ActuallySuper, Assoc = T>
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected type parameter `Self`, found type parameter `T`
   |
   = note: expected type parameter `Self`
              found type parameter `T`
   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
note: required for `Self` to implement `Mirror`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:20:42
   |
20 | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   |                              ---------   ^^^^^^     ^
   |                              |
   |                              unsatisfied trait bound introduced here

error[E0277]: the size for values of type `Self` cannot be known at compilation time
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:10:1
   |
10 | trait Foo<T, U>: Super<ActuallySuper, Assoc = T>
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
   |
note: required for `Self` to implement `Mirror`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:20:42
   |
20 | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   |      -                                   ^^^^^^     ^
   |      |
   |      unsatisfied trait bound introduced here
help: consider further restricting `Self`
   |
10 | trait Foo<T, U>: Super<ActuallySuper, Assoc = T> + Sized
   |                                                  +++++++

error[E0271]: type mismatch resolving `<Self as Super<ActuallySuper>>::Assoc == Self`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:12:30
   |
10 | trait Foo<T, U>: Super<ActuallySuper, Assoc = T>
   | ------------------------------------------------
   | |         |
   | |         found type parameter
   | expected type parameter
11 | where
12 |     <Self as Mirror>::Assoc: Super,
   |                              ^^^^^ expected type parameter `Self`, found type parameter `T`
   |
   = note: expected type parameter `Self`
              found type parameter `T`
   = note: a type parameter was expected, but a different one was found; you might be missing a type parameter or trait bound
   = note: for more information, visit https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters
note: required for `Self` to implement `Mirror`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:20:42
   |
20 | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   |                              ---------   ^^^^^^     ^
   |                              |
   |                              unsatisfied trait bound introduced here

error[E0277]: the size for values of type `Self` cannot be known at compilation time
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:12:30
   |
12 |     <Self as Mirror>::Assoc: Super,
   |                              ^^^^^ doesn't have a size known at compile-time
   |
note: required for `Self` to implement `Mirror`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:20:42
   |
20 | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   |      -                                   ^^^^^^     ^
   |      |
   |      unsatisfied trait bound introduced here
help: consider further restricting `Self`
   |
10 | trait Foo<T, U>: Super<ActuallySuper, Assoc = T> + Sized
   |                                                  +++++++

error[E0046]: not all trait items implemented, missing: `Assoc`
  --> /tmp/icemaker_global_tempdir.YividecqGvDC/rustc_testrunner_tmpdir_reporting.xtUMdAxGNOpm/mvce.rs:20:1
   |
18 |     type Assoc: ?Sized;
   |     ------------------ `Assoc` from trait
19 | }
20 | impl<T: Super<ActuallySuper, Assoc = T>> Mirror for T {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `Assoc` in implementation

error: aborting due to 9 previous errors

Some errors have detailed explanations: E0046, E0107, E0271, E0277, E0601.
For more information about an error, try `rustc --explain E0046`.

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    C-bugCategory: This is a bug.E-needs-testCall for participation: An issue has been fixed and does not reproduce, but no test has been added.I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️S-has-mcveStatus: A Minimal Complete and Verifiable Example has been found for this issueT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

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