error: internal compiler error: `_` overridden by `_` for HirId when adding str to an iter chain

[rcorre]

Code

struct Function {
    name: String,
}

struct Module {
    functions: Vec<Function>,
}

impl Module {
    fn to_md(&self) -> String {
        "## Functions"
            + self
                .functions
                .iter()
                .map(|f| f.name)
                .collect::<Vec<_>>()
                .join("\n\n")
    }
}

fn main() {}

Meta

rustc --version --verbose:

rustc 1.88.0 (6b00bc388 2025-06-23)
binary: rustc
commit-hash: 6b00bc3880198600130e1cf62b8f8a93494488cc
commit-date: 2025-06-23
host: x86_64-unknown-linux-gnu
release: 1.88.0
LLVM version: 20.1.5

Error output

error: internal compiler error: `std::slice::Iter<'_, Function>` overridden by `std::slice::Iter<'_, Function>` for HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).15) in DefId(0:8 ~ main[4f53]::{impl#0}::to_md)

Backtrace

thread 'rustc' panicked at compiler/rustc_hir_typeck/src/gather_locals.rs:112:17:
assertion `left == right` failed
  left: Some(?14t)
 right: None
stack backtrace:
   0: __rustc::rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::assert_failed_inner
   3: core::panicking::assert_failed::<core::option::Option<rustc_middle::ty::Ty>, core::option::Option<rustc_middle::ty::Ty>>
   4: <rustc_hir_typeck::gather_locals::GatherLocalsVisitor as rustc_hir::intravisit::Visitor>::visit_pat
   5: rustc_hir_typeck::check::check_fn
   6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_closure
   7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
   8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_argument_types
   9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
  13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
  15: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  16: rustc_hir_typeck::check::check_fn
  17: rustc_hir_typeck::typeck_with_inspect::{closure#0}
      [... omitted 1 frame ...]
  18: rustc_hir_analysis::check_crate
  19: rustc_interface::passes::run_required_analyses
  20: rustc_interface::passes::analysis
      [... omitted 1 frame ...]
  21: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  22: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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: rustc 1.88.0 (6b00bc388 2025-06-23) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [typeck] type-checking `<impl at src/main.rs:9:1: 9:12>::to_md`
#1 [analysis] running analysis passes on this crate
end of query stack
note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error: this path really should be doomed...
  --> src/main.rs:12:13
   |
12 |             + self
   |             ^
   |
note: delayed at compiler/rustc_hir_typeck/src/op.rs:1003:28
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, &str>
         4: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
         7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         8: rustc_hir_typeck::check::check_fn
         9: rustc_hir_typeck::typeck_with_inspect::{closure#0}
        10: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        11: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        12: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        13: rustc_hir_analysis::check_crate
        14: rustc_interface::passes::run_required_analyses
        15: rustc_interface::passes::analysis
        16: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        17: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        18: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        19: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
        20: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        21: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
        22: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        23: std::sys::pal::unix::thread::Thread::new::thread_start
        24: start_thread
                   at ./nptl/pthread_create.c:447:8
        25: clone3
                   at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0
  --> src/main.rs:12:13
   |
12 |             + self
   |             ^

error: internal compiler error: `&Module` overridden by `&Module` for HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).18) in DefId(0:8 ~ main[4f53]::{impl#0}::to_md)
  --> src/main.rs:12:15
   |
12 |             + self
   |               ^^^^
   |
note: delayed at compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs:159:28
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
         4: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_field
         6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
        12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
        14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        15: rustc_hir_typeck::check::check_fn
        16: rustc_hir_typeck::typeck_with_inspect::{closure#0}
        17: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        19: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        20: rustc_hir_analysis::check_crate
        21: rustc_interface::passes::run_required_analyses
        22: rustc_interface::passes::analysis
        23: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        24: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        25: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        26: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
        27: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        28: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
        29: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        30: std::sys::pal::unix::thread::Thread::new::thread_start
        31: start_thread
                   at ./nptl/pthread_create.c:447:8
        32: clone3
                   at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0
  --> src/main.rs:12:15
   |
12 |             + self
   |               ^^^^

error: internal compiler error: while adjusting Expr { hir_id: HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).18), kind: Path(Resolved(None, Path { span: src/main.rs:12:15: 12:19 (#0), res: Local(HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).2)), segments: [PathSegment { ident: self#0, hir_id: HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).19), res: Local(HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).2)), args: None, infer_args: true }] })), span: src/main.rs:12:15: 12:19 (#0) }, can't compose [Deref(None) -> Module] and [Deref(None) -> Module]
  --> src/main.rs:12:15
   |
12 |             + self
   |               ^^^^
   |
note: delayed at compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs:348:36
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
         4: <rustc_hir_typeck::fn_ctxt::FnCtxt>::apply_adjustments
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_field
         6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
        12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
        14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        15: rustc_hir_typeck::check::check_fn
        16: rustc_hir_typeck::typeck_with_inspect::{closure#0}
        17: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        18: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        19: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        20: rustc_hir_analysis::check_crate
        21: rustc_interface::passes::run_required_analyses
        22: rustc_interface::passes::analysis
        23: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        24: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        25: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        26: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
        27: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        28: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
        29: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        30: std::sys::pal::unix::thread::Thread::new::thread_start
        31: start_thread
                   at ./nptl/pthread_create.c:447:8
        32: clone3
                   at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0
  --> src/main.rs:12:15
   |
12 |             + self
   |               ^^^^

error: internal compiler error: `Vec<Function>` overridden by `Vec<Function>` for HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).17) in DefId(0:8 ~ main[4f53]::{impl#0}::to_md)
  --> src/main.rs:12:15
   |
12 |               + self
   |  _______________^
13 | |                 .functions
   | |__________________________^
   |
note: delayed at compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs:159:28
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
         4: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
        10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
        12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        13: rustc_hir_typeck::check::check_fn
        14: rustc_hir_typeck::typeck_with_inspect::{closure#0}
        15: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        16: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        17: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        18: rustc_hir_analysis::check_crate
        19: rustc_interface::passes::run_required_analyses
        20: rustc_interface::passes::analysis
        21: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        22: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        23: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        24: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
        25: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        26: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
        27: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        28: std::sys::pal::unix::thread::Thread::new::thread_start
        29: start_thread
                   at ./nptl/pthread_create.c:447:8
        30: clone3
                   at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0
  --> src/main.rs:12:15
   |
12 |               + self
   |  _______________^
13 | |                 .functions
   | |__________________________^

error: internal compiler error: `std::slice::Iter<'_, Function>` overridden by `std::slice::Iter<'_, Function>` for HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).15) in DefId(0:8 ~ main[4f53]::{impl#0}::to_md)
  --> src/main.rs:12:15
   |
12 |               + self
   |  _______________^
13 | |                 .functions
14 | |                 .iter()
   | |_______________________^
   |
note: delayed at compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs:159:28
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
         4: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
         9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
        11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        12: rustc_hir_typeck::check::check_fn
        13: rustc_hir_typeck::typeck_with_inspect::{closure#0}
        14: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        15: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        16: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        17: rustc_hir_analysis::check_crate
        18: rustc_interface::passes::run_required_analyses
        19: rustc_interface::passes::analysis
        20: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        21: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        22: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        23: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
        24: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        25: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
        26: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        27: std::sys::pal::unix::thread::Thread::new::thread_start
        28: start_thread
                   at ./nptl/pthread_create.c:447:8
        29: clone3
                   at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0
  --> src/main.rs:12:15
   |
12 |               + self
   |  _______________^
13 | |                 .functions
14 | |                 .iter()
   | |_______________________^

error: internal compiler error: `_` overridden by `_` for HirId(DefId(0:8 ~ main[4f53]::{impl#0}::to_md).26) in DefId(0:8 ~ main[4f53]::{impl#0}::to_md)
  --> src/main.rs:15:23
   |
15 |                 .map(|f| f.name)
   |                       ^
   |
note: delayed at compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs:159:28
         0: <rustc_errors::DiagCtxtInner>::emit_diagnostic
         1: <rustc_errors::DiagCtxtHandle>::emit_diagnostic
         2: <rustc_span::ErrorGuaranteed as rustc_errors::diagnostic::EmissionGuarantee>::emit_producing_guarantee
         3: <rustc_errors::DiagCtxtHandle>::span_delayed_bug::<rustc_span::span_encoding::Span, alloc::string::String>
         4: <dyn rustc_hir_analysis::hir_ty_lowering::HirTyLowerer>::lower_ty
         5: <rustc_hir_typeck::fn_ctxt::FnCtxt>::supplied_sig_of_closure
         6: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_closure
         7: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
         8: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_argument_types
         9: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        10: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        11: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        12: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_overloaded_binop
        13: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        14: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_block
        15: <rustc_hir_typeck::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
        16: rustc_hir_typeck::check::check_fn
        17: rustc_hir_typeck::typeck_with_inspect::{closure#0}
        18: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::typeck::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 8]>>
        19: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_data_structures::vec_cache::VecCache<rustc_span::def_id::LocalDefId, rustc_middle::query::erase::Erased<[u8; 8]>, rustc_query_system::dep_graph::graph::DepNodeIndex>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        20: rustc_query_impl::query_impl::typeck::get_query_non_incr::__rust_end_short_backtrace
        21: rustc_hir_analysis::check_crate
        22: rustc_interface::passes::run_required_analyses
        23: rustc_interface::passes::analysis
        24: rustc_query_impl::plumbing::__rust_begin_short_backtrace::<rustc_query_impl::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle::query::erase::Erased<[u8; 0]>>
        25: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::DynamicConfig<rustc_query_system::query::caches::SingleCache<rustc_middle::query::erase::Erased<[u8; 0]>>, false, false, false>, rustc_query_impl::plumbing::QueryCtxt, false>
        26: rustc_query_impl::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
        27: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
        28: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
        29: std::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
        30: <<std::thread::Builder>::spawn_unchecked_<rustc_interface::util::run_in_thread_with_globals<rustc_interface::util::run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
        31: std::sys::pal::unix::thread::Thread::new::thread_start
        32: start_thread
                   at ./nptl/pthread_create.c:447:8
        33: clone3
                   at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0
  --> src/main.rs:15:23
   |
15 |                 .map(|f| f.name)
   |                       ^

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.88.0 (6b00bc388 2025-06-23) running on x86_64-unknown-linux-gnu

query stack during panic:
end of query stack

[cyrgani]

Thanks for the report. This is already fixed on beta (by #140827) and has the same root cause as #143188 and several other issues.
Closing this as there is not much left to do right now other than waiting for the next release, which will happen in 16 days.