ICE: `can't get the span of an arbitrary parsed attribute`

[matthiaskrgr]

auto-reduced (treereduce-rust):

#[inline]
#[track_caller]
macro_rules! contained {
    () => {};
}

original:

#[inline]
#[track_caller]
macro_rules! contained { () => {} }

pub fn main() {}

Version information

rustc 1.89.0-nightly (3b97f1308 2025-06-20)
binary: rustc
commit-hash: 3b97f1308ff72016a4aaa93fbe6d09d4d6427815
commit-date: 2025-06-20
host: x86_64-unknown-linux-gnu
release: 1.89.0-nightly
LLVM version: 20.1.7

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

Program output

warning: unused macro definition: `contained`
 --> /tmp/icemaker_global_tempdir.h2zBL4aoaUWH/rustc_testrunner_tmpdir_reporting.EsRoILp2XH1B/mvce.rs:3:14
  |
3 | macro_rules! contained {
  |              ^^^^^^^^^
  |
  = note: `#[warn(unused_macros)]` on by default

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.h2zBL4aoaUWH/rustc_testrunner_tmpdir_reporting.EsRoILp2XH1B/mvce.rs:5:2
  |
5 | }
  |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.h2zBL4aoaUWH/rustc_testrunner_tmpdir_reporting.EsRoILp2XH1B/mvce.rs`

error[E0518]: attribute should be applied to function or closure
 --> /tmp/icemaker_global_tempdir.h2zBL4aoaUWH/rustc_testrunner_tmpdir_reporting.EsRoILp2XH1B/mvce.rs:1:1
  |
1 | #[inline]
  | ^^^^^^^^^ not a function or closure

warning: `#[track_caller]` is ignored on struct fields, match arms and macro defs
 --> /tmp/icemaker_global_tempdir.h2zBL4aoaUWH/rustc_testrunner_tmpdir_reporting.EsRoILp2XH1B/mvce.rs:2:1
  |
2 | #[track_caller]
  | ^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_attributes)]` on by default


thread 'rustc' panicked at /rustc-dev/3b97f1308ff72016a4aaa93fbe6d09d4d6427815/compiler/rustc_hir/src/hir.rs:1305:18:
can't get the span of an arbitrary parsed attribute: Parsed(Inline(Hint, /tmp/icemaker_global_tempdir.h2zBL4aoaUWH/rustc_testrunner_tmpdir_reporting.EsRoILp2XH1B/mvce.rs:1:1: 1:10 (#0)))
stack backtrace:
   0:     0x796ff7ce3033 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hdb1beb1efd036030
   1:     0x796ff8402d3f - core::fmt::write::h6fde5d988b046e43
   2:     0x796ff7cd8cc3 - std::io::Write::write_fmt::hfdc56ad9972213fb
   3:     0x796ff7ce2e92 - std::sys::backtrace::BacktraceLock::print::h7d50fbfbc01ef440
   4:     0x796ff7ce698a - std::panicking::default_hook::{{closure}}::h2d0b345b2d72c7b1
   5:     0x796ff7ce650f - std::panicking::default_hook::he0e1084842380634
   6:     0x796ff6ddc397 - std[6b85dd0cacdad3fb]::panicking::update_hook::<alloc[e197c52ffb0c953d]::boxed::Box<rustc_driver_impl[b5010b6a00a10337]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x796ff7ce71db - std::panicking::rust_panic_with_hook::h551040e3eccc63b8
   8:     0x796ff7ce6eda - std::panicking::begin_panic_handler::{{closure}}::h82732907cb122ecc
   9:     0x796ff7ce3509 - std::sys::backtrace::__rust_end_short_backtrace::h8d0b6d7b81e6f1ec
  10:     0x796ff7ce6bbd - __rustc[e49b1424bdfe04fc]::rust_begin_unwind
  11:     0x796ff448fbc0 - core::panicking::panic_fmt::h2de75984da6179f3
  12:     0x796ff8ae0d9f - <rustc_passes[ed7886fbdff4a823]::check_attr::CheckAttrVisitor>::check_attributes
  13:     0x796ff8ad7c86 - <rustc_passes[ed7886fbdff4a823]::check_attr::CheckAttrVisitor as rustc_hir[cd02d9627a3ada87]::intravisit::Visitor>::visit_item
  14:     0x796ff8ad71bf - rustc_passes[ed7886fbdff4a823]::check_attr::check_mod_attrs
  15:     0x796ff8ad7061 - rustc_query_impl[7d775a893a945633]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7d775a893a945633]::query_impl::check_mod_attrs::dynamic_query::{closure#2}::{closure#0}, rustc_middle[cffb9c37e6e9a24b]::query::erase::Erased<[u8; 0usize]>>
  16:     0x796ff928d058 - rustc_query_system[2228cb53b85e8de8]::query::plumbing::try_execute_query::<rustc_query_impl[7d775a893a945633]::DynamicConfig<rustc_query_system[2228cb53b85e8de8]::query::caches::DefaultCache<rustc_span[fb51e5d36bb23ffe]::def_id::LocalModDefId, rustc_middle[cffb9c37e6e9a24b]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[7d775a893a945633]::plumbing::QueryCtxt, false>
  17:     0x796ff928cd7d - rustc_query_impl[7d775a893a945633]::query_impl::check_mod_attrs::get_query_non_incr::__rust_end_short_backtrace
  18:     0x796ff928ca1b - <rustc_middle[cffb9c37e6e9a24b]::ty::context::TyCtxt>::par_hir_for_each_module::<rustc_interface[400f48cd83754571]::passes::run_required_analyses::{closure#0}::{closure#0}::{closure#1}::{closure#0}>::{closure#0}
  19:     0x796ff8ed7e8b - rustc_interface[400f48cd83754571]::passes::analysis
  20:     0x796ff8ed7bad - rustc_query_impl[7d775a893a945633]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[7d775a893a945633]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[cffb9c37e6e9a24b]::query::erase::Erased<[u8; 0usize]>>
  21:     0x796ff94a1d3c - rustc_query_system[2228cb53b85e8de8]::query::plumbing::try_execute_query::<rustc_query_impl[7d775a893a945633]::DynamicConfig<rustc_query_system[2228cb53b85e8de8]::query::caches::SingleCache<rustc_middle[cffb9c37e6e9a24b]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[7d775a893a945633]::plumbing::QueryCtxt, false>
  22:     0x796ff94a1a12 - rustc_query_impl[7d775a893a945633]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  23:     0x796ff960ee96 - rustc_interface[400f48cd83754571]::passes::create_and_enter_global_ctxt::<core[913fe49cdece82e8]::option::Option<rustc_interface[400f48cd83754571]::queries::Linker>, rustc_driver_impl[b5010b6a00a10337]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  24:     0x796ff9627963 - rustc_interface[400f48cd83754571]::interface::run_compiler::<(), rustc_driver_impl[b5010b6a00a10337]::run_compiler::{closure#0}>::{closure#1}
  25:     0x796ff9651402 - std[6b85dd0cacdad3fb]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[400f48cd83754571]::util::run_in_thread_with_globals<rustc_interface[400f48cd83754571]::util::run_in_thread_pool_with_globals<rustc_interface[400f48cd83754571]::interface::run_compiler<(), rustc_driver_impl[b5010b6a00a10337]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  26:     0x796ff96510e6 - <<std[6b85dd0cacdad3fb]::thread::Builder>::spawn_unchecked_<rustc_interface[400f48cd83754571]::util::run_in_thread_with_globals<rustc_interface[400f48cd83754571]::util::run_in_thread_pool_with_globals<rustc_interface[400f48cd83754571]::interface::run_compiler<(), rustc_driver_impl[b5010b6a00a10337]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[913fe49cdece82e8]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  27:     0x796ff964f73d - std::sys::pal::unix::thread::Thread::new::thread_start::ha32bf3e026b53de8
  28:     0x796ff30a57eb - <unknown>
  29:     0x796ff312918c - <unknown>
  30:                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 1.89.0-nightly (3b97f1308 2025-06-20) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [check_mod_attrs] checking attributes in top-level module
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors; 2 warnings emitted

Some errors have detailed explanations: E0518, E0601.
For more information about an error, try `rustc --explain E0518`.

[matthiaskrgr]

bisects to #138165

[matthiaskrgr]

on current stable:

warning: unused macro definition: `contained`
 --> a.rs:3:14
  |
3 | macro_rules! contained { () => {} }
  |              ^^^^^^^^^
  |
  = note: `#[warn(unused_macros)]` on by default

error[E0518]: attribute should be applied to function or closure
 --> a.rs:1:1
  |
1 | #[inline]
  | ^^^^^^^^^ not a function or closure

warning: `#[inline]` is ignored on struct fields, match arms and macro defs
 --> a.rs:1:1
  |
1 | #[inline]
  | ^^^^^^^^^
  |
  = note: `#[warn(unused_attributes)]` on by default

warning: `#[track_caller]` is ignored on struct fields, match arms and macro defs
 --> a.rs:1:1
  |
1 | #[inline]
  | ^^^^^^^^^

warning: `#[track_caller]` is ignored on struct fields, match arms and macro defs
 --> a.rs:2:1
  |
2 | #[track_caller]
  | ^^^^^^^^^^^^^^^

[mejrs]

It might be fixed by #142552 (haven't checked) but personally I do not believe that that approach is worth it. I think the best path forward (at least for now) is to change every parsed attribute to carry a span so we need not panic at

rust/compiler/rustc_hir/src/hir.rs

Lines 1298 to 1307 in 9c4ff56

	#[inline]
	fn span(&self) -> Span {
	match &self {
	Attribute::Unparsed(u) => u.span,
	// FIXME: should not be needed anymore when all attrs are parsed
	Attribute::Parsed(AttributeKind::Deprecation { span, .. }) => *span,
	Attribute::Parsed(AttributeKind::DocComment { span, .. }) => *span,
	a => panic!("can't get the span of an arbitrary parsed attribute: {a:?}"),
	}
	}

cc @jdonszelmann what do you think?