ICE: parse: builtin attribute "stable" not handled by CheckAttrVisitor

[matthiaskrgr]

auto-reduced (treereduce-rust):

struct S(#[stable::skip] u8, u16, u32);

original:

//@ check-pass

struct S(
    #[stable::skip] u8,
    u16,
    #[tokyo::main] u32,
);

fn main() { println!("{} landed on hir feet" , self . name); }

Version information

rustc 1.87.0-nightly (f5729cfed 2025-02-25)
binary: rustc
commit-hash: f5729cfed3c45e061e8a443677fc1d5ef9277df7
commit-date: 2025-02-25
host: x86_64-unknown-linux-gnu
release: 1.87.0-nightly
LLVM version: 20.1.0

Possibly related line of code:

rust/compiler/rustc_passes/src/check_attr.rs

Lines 295 to 307 in f5729cf

	Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
	Some(_) => {
	// FIXME: differentiate between unstable and internal attributes just
	// like we do with features instead of just accepting `rustc_`
	// attributes by name. That should allow trimming the above list, too.
	if !name.as_str().starts_with("rustc_") {
	span_bug!(
	attr.span(),
	"builtin attribute {name:?} not handled by `CheckAttrVisitor`"
	)
	}
	}
	None => (),

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

Program output

error[E0433]: failed to resolve: use of unresolved module or unlinked crate `stable`
 --> /tmp/icemaker_global_tempdir.Pu0CoxkwO27L/rustc_testrunner_tmpdir_reporting.RPLa6XCrNAt2/mvce.rs:1:12
  |
1 | struct S(#[stable::skip] u8, u16, u32);
  |            ^^^^^^ use of unresolved module or unlinked crate `stable`

error[E0601]: `main` function not found in crate `mvce`
 --> /tmp/icemaker_global_tempdir.Pu0CoxkwO27L/rustc_testrunner_tmpdir_reporting.RPLa6XCrNAt2/mvce.rs:1:40
  |
1 | struct S(#[stable::skip] u8, u16, u32);
  |                                        ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.Pu0CoxkwO27L/rustc_testrunner_tmpdir_reporting.RPLa6XCrNAt2/mvce.rs`

error: internal compiler error: compiler/rustc_passes/src/check_attr.rs:301:41: builtin attribute "stable" not handled by `CheckAttrVisitor`
 --> /tmp/icemaker_global_tempdir.Pu0CoxkwO27L/rustc_testrunner_tmpdir_reporting.RPLa6XCrNAt2/mvce.rs:1:10
  |
1 | struct S(#[stable::skip] u8, u16, u32);
  |          ^^^^^^^^^^^^^^^


thread 'rustc' panicked at compiler/rustc_passes/src/check_attr.rs:301:41:
Box<dyn Any>
stack backtrace:
   0:     0x7751857b0f34 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hca18af6381e1367c
   1:     0x77518601622c - core::fmt::write::h5592619a5f30a24e
   2:     0x7751870dcbd1 - std::io::Write::write_fmt::hc543125416d93a55
   3:     0x7751857b0d92 - std::sys::backtrace::BacktraceLock::print::h2507b83f5fdb3698
   4:     0x7751857b359e - std::panicking::default_hook::{{closure}}::h25029c6d53322486
   5:     0x7751857b3174 - std::panicking::default_hook::hded85171c110cc3b
   6:     0x77518491a827 - std[581eff941795a880]::panicking::update_hook::<alloc[44b1b4d4d47dda6c]::boxed::Box<rustc_driver_impl[dcc8af57e0e84081]::install_ice_hook::{closure#1}>>::{closure#0}
   7:     0x7751857b3e13 - std::panicking::rust_panic_with_hook::hbe0a3b6f34c80380
   8:     0x775184956cd1 - std[581eff941795a880]::panicking::begin_panic::<rustc_errors[c0f9bdb3918293e2]::ExplicitBug>::{closure#0}
   9:     0x77518494b0e6 - std[581eff941795a880]::sys::backtrace::__rust_end_short_backtrace::<std[581eff941795a880]::panicking::begin_panic<rustc_errors[c0f9bdb3918293e2]::ExplicitBug>::{closure#0}, !>
  10:     0x77518494b0cb - std[581eff941795a880]::panicking::begin_panic::<rustc_errors[c0f9bdb3918293e2]::ExplicitBug>
  11:     0x7751849606c1 - <rustc_errors[c0f9bdb3918293e2]::diagnostic::BugAbort as rustc_errors[c0f9bdb3918293e2]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  12:     0x775184ea5f4c - <rustc_errors[c0f9bdb3918293e2]::DiagCtxtHandle>::span_bug::<rustc_span[159dd1552b739661]::span_encoding::Span, alloc[44b1b4d4d47dda6c]::string::String>
  13:     0x775184f27e1a - rustc_middle[e6f8bc74c8fc856c]::util::bug::opt_span_bug_fmt::<rustc_span[159dd1552b739661]::span_encoding::Span>::{closure#0}
  14:     0x775184f113aa - rustc_middle[e6f8bc74c8fc856c]::ty::context::tls::with_opt::<rustc_middle[e6f8bc74c8fc856c]::util::bug::opt_span_bug_fmt<rustc_span[159dd1552b739661]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  15:     0x775184f1121b - rustc_middle[e6f8bc74c8fc856c]::ty::context::tls::with_context_opt::<rustc_middle[e6f8bc74c8fc856c]::ty::context::tls::with_opt<rustc_middle[e6f8bc74c8fc856c]::util::bug::opt_span_bug_fmt<rustc_span[159dd1552b739661]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  16:     0x77518373ac07 - rustc_middle[e6f8bc74c8fc856c]::util::bug::span_bug_fmt::<rustc_span[159dd1552b739661]::span_encoding::Span>
  17:     0x7751863f8f9d - <rustc_passes[6ccbb36aefae929c]::check_attr::CheckAttrVisitor>::check_attributes
  18:     0x7751863f5d74 - <rustc_passes[6ccbb36aefae929c]::check_attr::CheckAttrVisitor as rustc_hir[2b60df8069066663]::intravisit::Visitor>::visit_item
  19:     0x77518640ba41 - rustc_passes[6ccbb36aefae929c]::check_attr::check_mod_attrs
  20:     0x77518640b9cb - rustc_query_impl[c32460660d187a22]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c32460660d187a22]::query_impl::check_mod_attrs::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e6f8bc74c8fc856c]::query::erase::Erased<[u8; 0usize]>>
  21:     0x7751870743c1 - rustc_query_system[e93ee9904dcaa7d1]::query::plumbing::try_execute_query::<rustc_query_impl[c32460660d187a22]::DynamicConfig<rustc_query_system[e93ee9904dcaa7d1]::query::caches::DefaultCache<rustc_span[159dd1552b739661]::def_id::LocalModDefId, rustc_middle[e6f8bc74c8fc856c]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[c32460660d187a22]::plumbing::QueryCtxt, false>
  22:     0x7751870740bf - rustc_query_impl[c32460660d187a22]::query_impl::check_mod_attrs::get_query_non_incr::__rust_end_short_backtrace
  23:     0x775187073c5c - <rustc_middle[e6f8bc74c8fc856c]::ty::context::TyCtxt>::par_hir_for_each_module::<rustc_interface[5317c0be442ff202]::passes::run_required_analyses::{closure#0}::{closure#0}::{closure#1}::{closure#0}>::{closure#0}
  24:     0x7751863b4f56 - rustc_interface[5317c0be442ff202]::passes::run_required_analyses
  25:     0x77518707633a - rustc_interface[5317c0be442ff202]::passes::analysis
  26:     0x775187076319 - rustc_query_impl[c32460660d187a22]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[c32460660d187a22]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[e6f8bc74c8fc856c]::query::erase::Erased<[u8; 0usize]>>
  27:     0x7751870d5e8b - rustc_query_system[e93ee9904dcaa7d1]::query::plumbing::try_execute_query::<rustc_query_impl[c32460660d187a22]::DynamicConfig<rustc_query_system[e93ee9904dcaa7d1]::query::caches::SingleCache<rustc_middle[e6f8bc74c8fc856c]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[c32460660d187a22]::plumbing::QueryCtxt, false>
  28:     0x7751870d5b79 - rustc_query_impl[c32460660d187a22]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  29:     0x77518715903c - rustc_interface[5317c0be442ff202]::passes::create_and_enter_global_ctxt::<core[f5b0be8ed3a1b4e]::option::Option<rustc_interface[5317c0be442ff202]::queries::Linker>, rustc_driver_impl[dcc8af57e0e84081]::run_compiler::{closure#0}::{closure#2}>::{closure#2}::{closure#0}
  30:     0x7751870e7ee0 - rustc_interface[5317c0be442ff202]::interface::run_compiler::<(), rustc_driver_impl[dcc8af57e0e84081]::run_compiler::{closure#0}>::{closure#1}
  31:     0x775186fa1ac8 - std[581eff941795a880]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[5317c0be442ff202]::util::run_in_thread_with_globals<rustc_interface[5317c0be442ff202]::util::run_in_thread_pool_with_globals<rustc_interface[5317c0be442ff202]::interface::run_compiler<(), rustc_driver_impl[dcc8af57e0e84081]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  32:     0x775186fa2274 - <<std[581eff941795a880]::thread::Builder>::spawn_unchecked_<rustc_interface[5317c0be442ff202]::util::run_in_thread_with_globals<rustc_interface[5317c0be442ff202]::util::run_in_thread_pool_with_globals<rustc_interface[5317c0be442ff202]::interface::run_compiler<(), rustc_driver_impl[dcc8af57e0e84081]::run_compiler::{closure#0}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[f5b0be8ed3a1b4e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  33:     0x775186fa376f - std::sys::pal::unix::thread::Thread::new::thread_start::h717201ab54b439ec
  34:     0x7751810a370a - <unknown>
  35:     0x775181127aac - <unknown>
  36:                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 1.87.0-nightly (f5729cfed 2025-02-25) 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 3 previous errors

Some errors have detailed explanations: E0433, E0601.
For more information about an error, try `rustc --explain E0433`.

[jdonszelmann]

@rustbot claim

[jdonszelmann]

this is a subtle bug where the attribute both isn't parsed with the new attr parsing system, nor is validated anymore (since validation used to validate even when stable was followed by more segments). In the future, we can automatically reject any attribute that isn't parsed using a new-style parser. However, until all of those are there, we can't reject any attribute simply because no parser parsed it since maybe that attribute simply doesn't have a new style parser yet.

So, after talking about it a little with others on discord we thought it's probably best to keep these ICEs around. this used to be an error, now it's an ICE. Removing the ICE check would make new attributes without a new-style parser silently have real bugs which are harder to find and which is a bit spookier than this ICE in rare cases.

This does mean that any attribute we convert to a new style parser will have a corresponding bug exactly like this one where the first segment is a valid new-style attribute and we don't validate it causing this ICE. We can remove the check completely when all attrs are converted, because we can simply exhaustively match on the enum of AttributeKinds making this a compile time error.

Feel free to assign any issue exactly like this one to me, I'll close them all in a few months.