ICE: kcfi: `expected item, found (root_crate)`

[matthiaskrgr]

auto-reduced (treereduce-rust):

fn foo(_a: &str) {}

fn main() {
    let x = foo as fn(&'static str);
}

original:

fn foo(_a: &str) {}

fn main() {
    let x = foo as fn(&'static str);
    
    let _ = x == foo;
}

Version information

rustc 1.79.0-nightly (537aab7a2 2024-04-08)
binary: rustc
commit-hash: 537aab7a2e7fe9cdf50b5ff18485e0793cd8db62
commit-date: 2024-04-08
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.3

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zsanitizer=kcfi -Cpanic=abort

Program output

warning: unused variable: `x`
 --> /tmp/icemaker_global_tempdir.tprpAuJLOe5z/rustc_testrunner_tmpdir_reporting.5hObCDEs74yr/mvce.rs:4:9
  |
4 |     let x = foo as fn(&'static str);
  |         ^ help: if this is intentional, prefix it with an underscore: `_x`
  |
  = note: `#[warn(unused_variables)]` on by default

error: internal compiler error: compiler/rustc_middle/src/hir/map/mod.rs:668:18: expected item, found (root_crate)

thread 'rustc' panicked at compiler/rustc_middle/src/hir/map/mod.rs:668:18:
Box<dyn Any>
stack backtrace:
   0:     0x75c6cf428885 - std::backtrace_rs::backtrace::libunwind::trace::h3c5d6be2ca224618
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x75c6cf428885 - std::backtrace_rs::backtrace::trace_unsynchronized::h07f25bfbbc81f9b7
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x75c6cf428885 - std::sys_common::backtrace::_print_fmt::hf0313e0fd41b1242
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x75c6cf428885 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::ha80bcf755077e3a1
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x75c6cf477b4b - core::fmt::rt::Argument::fmt::hea7d7a647aef4433
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/core/src/fmt/rt.rs:142:9
   5:     0x75c6cf477b4b - core::fmt::write::h0eafe6836efd2236
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/core/src/fmt/mod.rs:1153:17
   6:     0x75c6cf41d47f - std::io::Write::write_fmt::hee25aa3e7912fe48
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/io/mod.rs:1843:15
   7:     0x75c6cf42865e - std::sys_common::backtrace::_print::h0c8b5670573775f7
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x75c6cf42865e - std::sys_common::backtrace::print::hb0c84899d27bc992
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x75c6cf42b159 - std::panicking::default_hook::{{closure}}::hdd10a62b37f83705
  10:     0x75c6cf42ae75 - std::panicking::default_hook::h491d7bd053f3c065
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/panicking.rs:291:9
  11:     0x75c6cbc5be5f - std[8cce646dcc9f51a2]::panicking::update_hook::<alloc[7e5e1bdade7884f3]::boxed::Box<rustc_driver_impl[b1693766bfe96bed]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x75c6cf42b85c - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h673a5ec9e27814ea
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/alloc/src/boxed.rs:2032:9
  13:     0x75c6cf42b85c - std::panicking::rust_panic_with_hook::h2f18055510e9d6ac
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/panicking.rs:792:13
  14:     0x75c6cbc8bed4 - std[8cce646dcc9f51a2]::panicking::begin_panic::<rustc_errors[6ec141f8b50a2d31]::ExplicitBug>::{closure#0}
  15:     0x75c6cbc88c46 - std[8cce646dcc9f51a2]::sys_common::backtrace::__rust_end_short_backtrace::<std[8cce646dcc9f51a2]::panicking::begin_panic<rustc_errors[6ec141f8b50a2d31]::ExplicitBug>::{closure#0}, !>
  16:     0x75c6cbc88926 - std[8cce646dcc9f51a2]::panicking::begin_panic::<rustc_errors[6ec141f8b50a2d31]::ExplicitBug>
  17:     0x75c6cbc952d1 - <rustc_errors[6ec141f8b50a2d31]::diagnostic::BugAbort as rustc_errors[6ec141f8b50a2d31]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x75c6cc13650c - rustc_middle[29872c107b60a246]::util::bug::opt_span_bug_fmt::<rustc_span[c8203a7ebedcd79e]::span_encoding::Span>::{closure#0}
  19:     0x75c6cc11dfda - rustc_middle[29872c107b60a246]::ty::context::tls::with_opt::<rustc_middle[29872c107b60a246]::util::bug::opt_span_bug_fmt<rustc_span[c8203a7ebedcd79e]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x75c6cc11de5b - rustc_middle[29872c107b60a246]::ty::context::tls::with_context_opt::<rustc_middle[29872c107b60a246]::ty::context::tls::with_opt<rustc_middle[29872c107b60a246]::util::bug::opt_span_bug_fmt<rustc_span[c8203a7ebedcd79e]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x75c6c9cff810 - rustc_middle[29872c107b60a246]::util::bug::bug_fmt
  22:     0x75c6cd31f46c - <rustc_middle[29872c107b60a246]::hir::map::Map>::expect_item
  23:     0x75c6cd2ae9f2 - rustc_query_impl[51661ff1e116d73e]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[51661ff1e116d73e]::query_impl::associated_item::dynamic_query::{closure#2}::{closure#0}, rustc_middle[29872c107b60a246]::query::erase::Erased<[u8; 40usize]>>
  24:     0x75c6cd2adc7a - rustc_query_system[2cf76174bd7e0814]::query::plumbing::try_execute_query::<rustc_query_impl[51661ff1e116d73e]::DynamicConfig<rustc_query_system[2cf76174bd7e0814]::query::caches::DefIdCache<rustc_middle[29872c107b60a246]::query::erase::Erased<[u8; 40usize]>>, false, false, false>, rustc_query_impl[51661ff1e116d73e]::plumbing::QueryCtxt, false>
  25:     0x75c6cd2ad970 - rustc_query_impl[51661ff1e116d73e]::query_impl::associated_item::get_query_non_incr::__rust_end_short_backtrace
  26:     0x75c6cda1cccc - rustc_middle[29872c107b60a246]::query::plumbing::query_get_at::<rustc_query_system[2cf76174bd7e0814]::query::caches::DefIdCache<rustc_middle[29872c107b60a246]::query::erase::Erased<[u8; 40usize]>>>
  27:     0x75c6ce69f520 - <rustc_middle[29872c107b60a246]::ty::instance::Instance>::resolve_for_fn_ptr.cold
  28:     0x75c6cda1696b - rustc_monomorphize[a54e4eb903c076d9]::collector::visit_fn_use
  29:     0x75c6ca7db067 - rustc_monomorphize[a54e4eb903c076d9]::collector::collect_items_rec::{closure#0}
  30:     0x75c6cde415e6 - rustc_monomorphize[a54e4eb903c076d9]::collector::collect_items_rec
  31:     0x75c6cde3c0ac - rustc_monomorphize[a54e4eb903c076d9]::partitioning::collect_and_partition_mono_items
  32:     0x75c6cde3b6a8 - rustc_query_impl[51661ff1e116d73e]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[51661ff1e116d73e]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2}::{closure#0}, rustc_middle[29872c107b60a246]::query::erase::Erased<[u8; 24usize]>>
  33:     0x75c6cde3b68d - <rustc_query_impl[51661ff1e116d73e]::query_impl::collect_and_partition_mono_items::dynamic_query::{closure#2} as core[7ebb3dbf9c5383ca]::ops::function::FnOnce<(rustc_middle[29872c107b60a246]::ty::context::TyCtxt, ())>>::call_once
  34:     0x75c6cde38214 - rustc_query_system[2cf76174bd7e0814]::query::plumbing::try_execute_query::<rustc_query_impl[51661ff1e116d73e]::DynamicConfig<rustc_query_system[2cf76174bd7e0814]::query::caches::SingleCache<rustc_middle[29872c107b60a246]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[51661ff1e116d73e]::plumbing::QueryCtxt, false>
  35:     0x75c6cde37f0b - rustc_query_impl[51661ff1e116d73e]::query_impl::collect_and_partition_mono_items::get_query_non_incr::__rust_end_short_backtrace
  36:     0x75c6cdfa4aaa - rustc_codegen_ssa[1df6559decbf1b9a]::base::codegen_crate::<rustc_codegen_llvm[daf017fde14aa476]::LlvmCodegenBackend>
  37:     0x75c6cdead502 - <rustc_codegen_llvm[daf017fde14aa476]::LlvmCodegenBackend as rustc_codegen_ssa[1df6559decbf1b9a]::traits::backend::CodegenBackend>::codegen_crate
  38:     0x75c6cdeace85 - rustc_interface[e7aac3eeb74c4c0c]::passes::start_codegen
  39:     0x75c6cdeac4ee - <rustc_interface[e7aac3eeb74c4c0c]::queries::Queries>::codegen_and_build_linker
  40:     0x75c6cdceecd3 - rustc_interface[e7aac3eeb74c4c0c]::interface::run_compiler::<core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>, rustc_driver_impl[b1693766bfe96bed]::run_compiler::{closure#0}>::{closure#0}
  41:     0x75c6cddcc01d - std[8cce646dcc9f51a2]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[e7aac3eeb74c4c0c]::util::run_in_thread_with_globals<rustc_interface[e7aac3eeb74c4c0c]::util::run_in_thread_pool_with_globals<rustc_interface[e7aac3eeb74c4c0c]::interface::run_compiler<core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>, rustc_driver_impl[b1693766bfe96bed]::run_compiler::{closure#0}>::{closure#0}, core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>>::{closure#0}, core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>>
  42:     0x75c6cddcbe2a - <<std[8cce646dcc9f51a2]::thread::Builder>::spawn_unchecked_<rustc_interface[e7aac3eeb74c4c0c]::util::run_in_thread_with_globals<rustc_interface[e7aac3eeb74c4c0c]::util::run_in_thread_pool_with_globals<rustc_interface[e7aac3eeb74c4c0c]::interface::run_compiler<core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>, rustc_driver_impl[b1693766bfe96bed]::run_compiler::{closure#0}>::{closure#0}, core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>>::{closure#0}, core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[7ebb3dbf9c5383ca]::result::Result<(), rustc_span[c8203a7ebedcd79e]::ErrorGuaranteed>>::{closure#1} as core[7ebb3dbf9c5383ca]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  43:     0x75c6cf43528b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hea2f762c1fe3db14
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/alloc/src/boxed.rs:2018:9
  44:     0x75c6cf43528b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h79ea2eedb7e4df53
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/alloc/src/boxed.rs:2018:9
  45:     0x75c6cf43528b - std::sys::pal::unix::thread::Thread::new::thread_start::h83279d19c2446390
                               at /rustc/537aab7a2e7fe9cdf50b5ff18485e0793cd8db62/library/std/src/sys/pal/unix/thread.rs:108:17
  46:     0x75c6cf1d355a - <unknown>
  47:     0x75c6cf250a3c - <unknown>
  48:                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: rustc 1.79.0-nightly (537aab7a2 2024-04-08) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z sanitizer=kcfi -C panic=abort -Z dump-mir-dir=dir

query stack during panic:
#0 [associated_item] computing associated item data for `foo`
#1 [collect_and_partition_mono_items] collect_and_partition_mono_items
end of query stack
error: aborting due to 1 previous error; 1 warning emitted

[compiler-errors]

maybe fixed by #123635