ice `unexpected sort of node in fn_sig(): Item(Item`..`

[matthiaskrgr]

Summary

use std::iter::FromIterator;
use std::option::IntoIter as OptionIter;

fn eq<T: Eq>(a: T, b: T) -> bool { a == b }


macro_rules! tests {
    ($($expr:expr, $ty:ty, ($($test:expr),*);)+) => (pub fn main() {$({
        const C: $ty = $expr;
        assert!(eq(C($($test),*), $expr($($test),*)));
    })+})
}

tests! {
    FromIterator::from_iter, fn(OptionIter<i32>) -> Vec<i32>, (Some(5).into_iter());
}

Version

rustc 1.72.0-nightly (32d81eccd 2023-07-02)
binary: rustc
commit-hash: 32d81eccd64513bacef9dfa1574543ada6b45d85
commit-date: 2023-07-02
host: x86_64-unknown-linux-gnu
release: 1.72.0-nightly
LLVM version: 16.0.5

Error output

Backtrace

error: internal compiler error: compiler/rustc_hir_analysis/src/collect.rs:1175:13: unexpected sort of node in fn_sig(): Item(Item { ident: C#4, owner_id: DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C), kind: Const(Ty { hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).9), kind: BareFn(BareFnTy { unsafety: Normal, abi: Rust, generic_params: [], decl: FnDecl { inputs: [Ty { hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).1), kind: Path(Resolved(None, Path { span: ufcs-polymorphic-paths.rs:17:33: 17:48 (#0), res: Def(Struct, DefId(2:41611 ~ core[0662]::option::IntoIter)), segments: [PathSegment { ident: OptionIter#0, hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).4), res: Def(Struct, DefId(2:41611 ~ core[0662]::option::IntoIter)), args: Some(GenericArgs { args: [Type(Ty { hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).2), kind: Path(Resolved(None, Path { span: ufcs-polymorphic-paths.rs:17:44: 17:47 (#0), res: PrimTy(Int(I32)), segments: [PathSegment { ident: i32#0, hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).3), res: PrimTy(Int(I32)), args: None, infer_args: false }] })), span: ufcs-polymorphic-paths.rs:17:44: 17:47 (#0) })], bindings: [], parenthesized: No, span_ext: ufcs-polymorphic-paths.rs:17:43: 17:48 (#0) }), infer_args: false }] })), span: ufcs-polymorphic-paths.rs:17:33: 17:48 (#0) }], output: Return(Ty { hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).5), kind: Path(Resolved(None, Path { span: ufcs-polymorphic-paths.rs:17:53: 17:61 (#0), res: Def(Struct, DefId(5:6719 ~ alloc[6729]::vec::Vec)), segments: [PathSegment { ident: Vec#0, hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).8), res: Def(Struct, DefId(5:6719 ~ alloc[6729]::vec::Vec)), args: Some(GenericArgs { args: [Type(Ty { hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).6), kind: Path(Resolved(None, Path { span: ufcs-polymorphic-paths.rs:17:57: 17:60 (#0), res: PrimTy(Int(I32)), segments: [PathSegment { ident: i32#0, hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).7), res: PrimTy(Int(I32)), args: None, infer_args: false }] })), span: ufcs-polymorphic-paths.rs:17:57: 17:60 (#0) })], bindings: [], parenthesized: No, span_ext: ufcs-polymorphic-paths.rs:17:56: 17:61 (#0) }), infer_args: false }] })), span: ufcs-polymorphic-paths.rs:17:53: 17:61 (#0) }), c_variadic: false, implicit_self: None, lifetime_elision_allowed: false }, param_names: [#0] }), span: ufcs-polymorphic-paths.rs:17:30: 17:61 (#0) }, BodyId { hir_id: HirId(DefId(0:9 ~ ufcs_polymorphic_paths[8e59]::main::C).10) }), span: ufcs-polymorphic-paths.rs:11:9: 11:30 (#4), vis_span: ufcs-polymorphic-paths.rs:11:9: 11:9 (#4) })

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/compiler/rustc_errors/src/lib.rs:1650:9
stack backtrace:
 0:     0x7f9f0edf4e31 - std::backtrace_rs::backtrace::libunwind::trace::h1aa701a6f07f9bbb
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
 1:     0x7f9f0edf4e31 - std::backtrace_rs::backtrace::trace_unsynchronized::h9ae9d6e8c5c72b62
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
 2:     0x7f9f0edf4e31 - std::sys_common::backtrace::_print_fmt::hfaef5052365cf665
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/sys_common/backtrace.rs:65:5
 3:     0x7f9f0edf4e31 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::haeef210b4538668a
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/sys_common/backtrace.rs:44:22
 4:     0x7f9f0ee565df - core::fmt::rt::Argument::fmt::h33bbbf421d58fca4
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/core/src/fmt/rt.rs:138:9
 5:     0x7f9f0ee565df - core::fmt::write::he44b856c4b45f787
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/core/src/fmt/mod.rs:1094:21
 6:     0x7f9f0ede7967 - std::io::Write::write_fmt::hded42ab4301c934e
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/io/mod.rs:1714:15
 7:     0x7f9f0edf4c45 - std::sys_common::backtrace::_print::h12bd163b4566637e
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/sys_common/backtrace.rs:47:5
 8:     0x7f9f0edf4c45 - std::sys_common::backtrace::print::h78df3905035fd00a
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/sys_common/backtrace.rs:34:9
 9:     0x7f9f0edf79f3 - std::panicking::default_hook::{{closure}}::h588795889886bd81
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/panicking.rs:269:22
10:     0x7f9f0edf7784 - std::panicking::default_hook::h8f33142631f33dcd
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/panicking.rs:288:9
11:     0x7f9f0dc0da9b - <rustc_driver_impl[aedb6f0638cc4997]::install_ice_hook::{closure#0} as core[66236b962f4f8b3]::ops::function::FnOnce<(&core[66236b962f4f8b3]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
12:     0x7f9f0edf821e - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h3d4c5f73aa534950
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/alloc/src/boxed.rs:2024:9
13:     0x7f9f0edf821e - std::panicking::rust_panic_with_hook::hf8beb94f0fe0d1f3
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/panicking.rs:709:13
14:     0x7f9f0e1b9a31 - std[d57842597b9c3de2]::panicking::begin_panic::<rustc_errors[9487b0fe91249864]::ExplicitBug>::{closure#0}
15:     0x7f9f0e1b9546 - std[d57842597b9c3de2]::sys_common::backtrace::__rust_end_short_backtrace::<std[d57842597b9c3de2]::panicking::begin_panic<rustc_errors[9487b0fe91249864]::ExplicitBug>::{closure#0}, !>
16:     0x7f9f0e19a596 - std[d57842597b9c3de2]::panicking::begin_panic::<rustc_errors[9487b0fe91249864]::ExplicitBug>
17:     0x7f9f0e1324c4 - <rustc_errors[9487b0fe91249864]::HandlerInner>::bug::<alloc[67293afed414a74a]::string::String>
18:     0x7f9f0e132346 - <rustc_errors[9487b0fe91249864]::Handler>::bug::<alloc[67293afed414a74a]::string::String>
19:     0x7f9f0e10058c - rustc_middle[b999effd84d4d25b]::util::bug::opt_span_bug_fmt::<rustc_span[175a833f7d8153f1]::span_encoding::Span>::{closure#0}
20:     0x7f9f0e1002ea - rustc_middle[b999effd84d4d25b]::ty::context::tls::with_opt::<rustc_middle[b999effd84d4d25b]::util::bug::opt_span_bug_fmt<rustc_span[175a833f7d8153f1]::span_encoding::Span>::{closure#0}, !>::{closure#0}
21:     0x7f9f0e1002ba - rustc_middle[b999effd84d4d25b]::ty::context::tls::with_context_opt::<rustc_middle[b999effd84d4d25b]::ty::context::tls::with_opt<rustc_middle[b999effd84d4d25b]::util::bug::opt_span_bug_fmt<rustc_span[175a833f7d8153f1]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
22:     0x7f9f0c38e8ad - rustc_middle[b999effd84d4d25b]::util::bug::bug_fmt
23:     0x7f9f0c104cad - rustc_hir_analysis[2ab22ce4e0abfec2]::collect::fn_sig
24:     0x7f9f0c1046bc - rustc_query_impl[b332ceb5079bcc8]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b332ceb5079bcc8]::query_impl::fn_sig::dynamic_query::{closure#2}::{closure#0}, rustc_middle[b999effd84d4d25b]::query::erase::Erased<[u8; 24usize]>>
25:     0x7f9f0c104675 - <rustc_query_impl[b332ceb5079bcc8]::query_impl::fn_sig::dynamic_query::{closure#2} as core[66236b962f4f8b3]::ops::function::FnOnce<(rustc_middle[b999effd84d4d25b]::ty::context::TyCtxt, rustc_span[175a833f7d8153f1]::def_id::DefId)>>::call_once
26:     0x7f9f0bcffa48 - rustc_query_system[16e9793ec34b9d59]::query::plumbing::try_execute_query::<rustc_query_impl[b332ceb5079bcc8]::DynamicConfig<rustc_query_system[16e9793ec34b9d59]::query::caches::DefaultCache<rustc_span[175a833f7d8153f1]::def_id::DefId, rustc_middle[b999effd84d4d25b]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[b332ceb5079bcc8]::plumbing::QueryCtxt, false>
27:     0x7f9f0d5aecb4 - rustc_query_impl[b332ceb5079bcc8]::query_impl::fn_sig::get_query_non_incr::__rust_end_short_backtrace
28:     0x55965374fac1 - rustc_middle[b999effd84d4d25b]::query::plumbing::query_get_at::<rustc_query_system[16e9793ec34b9d59]::query::caches::DefaultCache<rustc_span[175a833f7d8153f1]::def_id::DefId, rustc_middle[b999effd84d4d25b]::query::erase::Erased<[u8; 24usize]>>>
29:     0x559653771bad - <clippy_lints[9f662dfa9206825f]::useless_conversion::UselessConversion as rustc_lint[e2531b73e1252f52]::passes::LateLintPass>::check_expr
30:     0x7f9f0e044e66 - <rustc_lint[e2531b73e1252f52]::early::RuntimeCombinedEarlyLintPass as rustc_lint[e2531b73e1252f52]::passes::EarlyLintPass>::check_generic_arg
31:     0x7f9f0dfdf6c6 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
32:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
33:     0x7f9f0dfb04e8 - rustc_hir[7da11ae52209a363]::intravisit::walk_expr::<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>
34:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
35:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
36:     0x7f9f0dfb04e8 - rustc_hir[7da11ae52209a363]::intravisit::walk_expr::<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>
37:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
38:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
39:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
40:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
41:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
42:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
43:     0x7f9f0dfb058e - rustc_hir[7da11ae52209a363]::intravisit::walk_expr::<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>
44:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
45:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
46:     0x7f9f0dfaeeab - rustc_hir[7da11ae52209a363]::intravisit::walk_block::<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>
47:     0x7f9f0dfe0099 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_block
48:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
49:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
50:     0x7f9f0dfe0099 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_block
51:     0x7f9f0dfdf6d1 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>::with_lint_attrs::<<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr::{closure#0}::{closure#0}>
52:     0x7f9f0dfdff8c - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_expr
53:     0x7f9f0dfe03e5 - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_nested_body
54:     0x7f9f0dfe05ca - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_fn
55:     0x7f9f0dfb0883 - rustc_hir[7da11ae52209a363]::intravisit::walk_item::<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>
56:     0x7f9f0dfe0d2f - <rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass> as rustc_hir[7da11ae52209a363]::intravisit::Visitor>::visit_nested_item
57:     0x7f9f0dfb0108 - rustc_hir[7da11ae52209a363]::intravisit::walk_mod::<rustc_lint[e2531b73e1252f52]::late::LateContextAndPass<rustc_lint[e2531b73e1252f52]::late::RuntimeCombinedLateLintPass>>
58:     0x7f9f0d08246e - rustc_lint[e2531b73e1252f52]::late::late_lint_crate::<rustc_lint[e2531b73e1252f52]::BuiltinCombinedLateLintPass>
59:     0x7f9f0d081888 - <rustc_session[7e329d50d0b7b6ab]::session::Session>::time::<(), rustc_lint[e2531b73e1252f52]::late::check_crate<rustc_lint[e2531b73e1252f52]::BuiltinCombinedLateLintPass, rustc_interface[69a9f571ec0ef69d]::passes::analysis::{closure#5}::{closure#1}::{closure#2}::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>
60:     0x7f9f0d081723 - <rustc_session[7e329d50d0b7b6ab]::session::Session>::time::<(), rustc_interface[69a9f571ec0ef69d]::passes::analysis::{closure#5}::{closure#1}::{closure#2}::{closure#0}>
61:     0x7f9f0d0812d9 - std[d57842597b9c3de2]::panicking::try::<(), core[66236b962f4f8b3]::panic::unwind_safe::AssertUnwindSafe<rustc_interface[69a9f571ec0ef69d]::passes::analysis::{closure#5}::{closure#1}>>
62:     0x7f9f0d0806e0 - <rustc_session[7e329d50d0b7b6ab]::session::Session>::time::<(), rustc_interface[69a9f571ec0ef69d]::passes::analysis::{closure#5}>
63:     0x7f9f0d07e367 - rustc_interface[69a9f571ec0ef69d]::passes::analysis
64:     0x7f9f0d0fc8da - rustc_query_impl[b332ceb5079bcc8]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[b332ceb5079bcc8]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[b999effd84d4d25b]::query::erase::Erased<[u8; 1usize]>>
65:     0x7f9f0d0fc8c9 - <rustc_query_impl[b332ceb5079bcc8]::query_impl::analysis::dynamic_query::{closure#2} as core[66236b962f4f8b3]::ops::function::FnOnce<(rustc_middle[b999effd84d4d25b]::ty::context::TyCtxt, ())>>::call_once
66:     0x7f9f0d29b758 - rustc_query_system[16e9793ec34b9d59]::query::plumbing::try_execute_query::<rustc_query_impl[b332ceb5079bcc8]::DynamicConfig<rustc_query_system[16e9793ec34b9d59]::query::caches::SingleCache<rustc_middle[b999effd84d4d25b]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[b332ceb5079bcc8]::plumbing::QueryCtxt, false>
67:     0x7f9f0d29b529 - rustc_query_impl[b332ceb5079bcc8]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
68:     0x7f9f0ce8e735 - <rustc_middle[b999effd84d4d25b]::ty::context::GlobalCtxt>::enter::<rustc_driver_impl[aedb6f0638cc4997]::run_compiler::{closure#1}::{closure#2}::{closure#4}, core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>
69:     0x7f9f0ce8dd61 - <rustc_interface[69a9f571ec0ef69d]::interface::Compiler>::enter::<rustc_driver_impl[aedb6f0638cc4997]::run_compiler::{closure#1}::{closure#2}, core[66236b962f4f8b3]::result::Result<core[66236b962f4f8b3]::option::Option<rustc_interface[69a9f571ec0ef69d]::queries::Linker>, rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>
70:     0x7f9f0ce84885 - rustc_span[175a833f7d8153f1]::set_source_map::<core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>, rustc_interface[69a9f571ec0ef69d]::interface::run_compiler<core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>, rustc_driver_impl[aedb6f0638cc4997]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
71:     0x7f9f0ce83ca6 - <scoped_tls[6271c32cbaced029]::ScopedKey<rustc_span[175a833f7d8153f1]::SessionGlobals>>::set::<rustc_interface[69a9f571ec0ef69d]::interface::run_compiler<core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>, rustc_driver_impl[aedb6f0638cc4997]::run_compiler::{closure#1}>::{closure#0}, core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>
72:     0x7f9f0ce83256 - std[d57842597b9c3de2]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[69a9f571ec0ef69d]::util::run_in_thread_pool_with_globals<rustc_interface[69a9f571ec0ef69d]::interface::run_compiler<core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>, rustc_driver_impl[aedb6f0638cc4997]::run_compiler::{closure#1}>::{closure#0}, core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>
73:     0x7f9f0d49828e - <<std[d57842597b9c3de2]::thread::Builder>::spawn_unchecked_<rustc_interface[69a9f571ec0ef69d]::util::run_in_thread_pool_with_globals<rustc_interface[69a9f571ec0ef69d]::interface::run_compiler<core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>, rustc_driver_impl[aedb6f0638cc4997]::run_compiler::{closure#1}>::{closure#0}, core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[66236b962f4f8b3]::result::Result<(), rustc_span[175a833f7d8153f1]::ErrorGuaranteed>>::{closure#1} as core[66236b962f4f8b3]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
74:     0x7f9f0ee02695 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h224d71f7c1e19ed0
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/alloc/src/boxed.rs:2010:9
75:     0x7f9f0ee02695 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h9c133a1396147f3c
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/alloc/src/boxed.rs:2010:9
76:     0x7f9f0ee02695 - std::sys::unix::thread::Thread::new::thread_start::hb96c84e6fd62e1f0
                             at /rustc/32d81eccd64513bacef9dfa1574543ada6b45d85/library/std/src/sys/unix/thread.rs:108:17
77:     0x7f9f0a75244b - <unknown>
78:     0x7f9f0a7d5e40 - <unknown>
79:                0x0 - <unknown>

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: rustc 1.72.0-nightly (32d81eccd 2023-07-02) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [fn_sig] computing function signature of `main::C`
#1 [analysis] running analysis passes on this crate
end of query stack
note: Clippy version: clippy 0.1.72 (32d81ec 2023-07-02)

error: aborting due to previous error

[y21]

Smaller repro without the macros:

use std::option::IntoIter;

fn main() {
    const C: fn(IntoIter<i32>) -> IntoIter<i32> = <IntoIter<i32> as IntoIterator>::into_iter;
    C(Some(5).into_iter()); // ICE here
}

Seems like the useless_conversion lint assumes that since the parent expression of Some(5).into_iter() is a function call (C(...)), its path must point to an fn-like item, but here it does not. C is a const, but not a fn item, so fn_sig ICEs

@rustbot claim

[y21]

oh, hidden behind this ICE is also an FP.

It basically boils down to having a macro that expands an expr metavariable twice: once to trigger the lint, and again in a variable declaration with a type annotation, which would cause an error when removing the .into_iter(). Example:

use std::option::IntoIter;
fn takes_into_iter(_: impl IntoIterator<Item = i32>) {}

macro_rules! x {
    ($e:expr) => {
        takes_into_iter($e); // lint here because `.into_iter()` is "redundant"
        let _: IntoIter<i32> = $e; // removing `.into_iter()` leads to a type error here
    };
}

fn main() {
    x!(Some(5).into_iter());
}

I guess we shouldn't lint if the expression is not just from a macro expansion, but also part (i.e. an argument) of a macro call