ICE: ast lowering: `None`

[matthiaskrgr]

snippet:

trait MyTrait {
    #[doc = MyTrait]
    fn myfun();
}

Version information

rustc 1.78.0-nightly (8f359beca 2024-02-23)
binary: rustc
commit-hash: 8f359beca4e58bc3ae795a666301a8f47023044c
commit-date: 2024-02-23
host: x86_64-unknown-linux-gnu
release: 1.78.0-nightly
LLVM version: 18.1.0

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

Program output

thread 'rustc' panicked at compiler/rustc_ast_lowering/src/lib.rs:962:56:
called `Option::unwrap()` on a `None` value
stack backtrace:
   0:     0x7f51bb58caf6 - std::backtrace_rs::backtrace::libunwind::trace::h4d16db2f784877bc
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
   1:     0x7f51bb58caf6 - std::backtrace_rs::backtrace::trace_unsynchronized::h584b4a9b0240fa46
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f51bb58caf6 - std::sys_common::backtrace::_print_fmt::hd30229489add2f78
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f51bb58caf6 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h2c0d00d6b7d69808
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f51bb5dda7c - core::fmt::rt::Argument::fmt::hff9bfb4853f651d7
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/core/src/fmt/rt.rs:142:9
   5:     0x7f51bb5dda7c - core::fmt::write::h3421d3f24b10b162
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/core/src/fmt/mod.rs:1120:17
   6:     0x7f51bb5814bf - std::io::Write::write_fmt::hec18e9e87db322bb
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/io/mod.rs:1846:15
   7:     0x7f51bb58c8a4 - std::sys_common::backtrace::_print::hec336a3777e68e7b
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f51bb58c8a4 - std::sys_common::backtrace::print::hde3a6d5d13170337
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f51bb58f5eb - std::panicking::default_hook::{{closure}}::h4a4905d59aca1811
  10:     0x7f51bb58f339 - std::panicking::default_hook::h33a18ce8d018f6fd
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/panicking.rs:292:9
  11:     0x7f51be48467c - std[d1f7731e2ff5974d]::panicking::update_hook::<alloc[6711342ad6595d8]::boxed::Box<rustc_driver_impl[db1009755931a507]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f51bb58fd50 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h923e5082c0e2f790
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/alloc/src/boxed.rs:2030:9
  13:     0x7f51bb58fd50 - std::panicking::rust_panic_with_hook::he294011ca89c3e63
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/panicking.rs:783:13
  14:     0x7f51bb58fa59 - std::panicking::begin_panic_handler::{{closure}}::hd80de86623d4d7ef
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/panicking.rs:649:13
  15:     0x7f51bb58cfd6 - std::sys_common::backtrace::__rust_end_short_backtrace::h310587e2e5c29372
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7f51bb58f7c4 - rust_begin_unwind
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/panicking.rs:645:5
  17:     0x7f51bb5d9f95 - core::panicking::panic_fmt::h275e2499dd810de9
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/core/src/panicking.rs:72:14
  18:     0x7f51bb5da053 - core::panicking::panic::hc7e092584ec9d38c
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/core/src/panicking.rs:144:5
  19:     0x7f51bb5d9d26 - core::option::unwrap_failed::h2d0876c43db0d378
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/core/src/option.rs:1985:5
  20:     0x7f51bf9d53ef - <rustc_ast_lowering[ce393ffbb0c3f2c8]::LoweringContext>::lower_attrs
  21:     0x7f51bfaf11f1 - <rustc_ast_lowering[ce393ffbb0c3f2c8]::LoweringContext>::lower_assoc_item
  22:     0x7f51bfaee2d3 - <rustc_ast_lowering[ce393ffbb0c3f2c8]::item::ItemLowerer>::lower_node
  23:     0x7f51c0841e82 - rustc_ast_lowering[ce393ffbb0c3f2c8]::lower_to_hir
  24:     0x7f51c08415fc - rustc_query_impl[5f3fca9184d705d1]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5f3fca9184d705d1]::query_impl::hir_crate::dynamic_query::{closure#2}::{closure#0}, rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 8usize]>>
  25:     0x7f51c059388e - rustc_query_system[3c44b3ad726fdf36]::query::plumbing::try_execute_query::<rustc_query_impl[5f3fca9184d705d1]::DynamicConfig<rustc_query_system[3c44b3ad726fdf36]::query::caches::SingleCache<rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[5f3fca9184d705d1]::plumbing::QueryCtxt, false>
  26:     0x7f51c05933e0 - rustc_query_impl[5f3fca9184d705d1]::query_impl::hir_crate::get_query_non_incr::__rust_end_short_backtrace
  27:     0x7f51bfab91c3 - rustc_query_impl[5f3fca9184d705d1]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5f3fca9184d705d1]::query_impl::hir_attrs::dynamic_query::{closure#2}::{closure#0}, rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 8usize]>>
  28:     0x7f51bfab8723 - rustc_query_system[3c44b3ad726fdf36]::query::plumbing::try_execute_query::<rustc_query_impl[5f3fca9184d705d1]::DynamicConfig<rustc_query_system[3c44b3ad726fdf36]::query::caches::VecCache<rustc_hir[9af8e7cbf4ff6ec9]::hir_id::OwnerId, rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[5f3fca9184d705d1]::plumbing::QueryCtxt, false>
  29:     0x7f51bfab8489 - rustc_query_impl[5f3fca9184d705d1]::query_impl::hir_attrs::get_query_non_incr::__rust_end_short_backtrace
  30:     0x7f51bf81a62a - <rustc_middle[10e0138f1f482b76]::hir::map::Map>::attrs
  31:     0x7f51c0808003 - rustc_passes[caae405a59d13605]::entry::entry_fn
  32:     0x7f51c0807f98 - rustc_query_impl[5f3fca9184d705d1]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5f3fca9184d705d1]::query_impl::entry_fn::dynamic_query::{closure#2}::{closure#0}, rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 12usize]>>
  33:     0x7f51c0807f73 - <rustc_query_impl[5f3fca9184d705d1]::query_impl::entry_fn::dynamic_query::{closure#2} as core[bd87c62ae3a7b4ee]::ops::function::FnOnce<(rustc_middle[10e0138f1f482b76]::ty::context::TyCtxt, ())>>::call_once
  34:     0x7f51c080788a - rustc_query_system[3c44b3ad726fdf36]::query::plumbing::try_execute_query::<rustc_query_impl[5f3fca9184d705d1]::DynamicConfig<rustc_query_system[3c44b3ad726fdf36]::query::caches::SingleCache<rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 12usize]>>, false, false, false>, rustc_query_impl[5f3fca9184d705d1]::plumbing::QueryCtxt, false>
  35:     0x7f51c0807645 - rustc_query_impl[5f3fca9184d705d1]::query_impl::entry_fn::get_query_non_incr::__rust_end_short_backtrace
  36:     0x7f51c03edab4 - rustc_interface[94ec20dfe64cdcea]::passes::analysis
  37:     0x7f51c03ed9d9 - rustc_query_impl[5f3fca9184d705d1]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5f3fca9184d705d1]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 1usize]>>
  38:     0x7f51c0525643 - rustc_query_system[3c44b3ad726fdf36]::query::plumbing::try_execute_query::<rustc_query_impl[5f3fca9184d705d1]::DynamicConfig<rustc_query_system[3c44b3ad726fdf36]::query::caches::SingleCache<rustc_middle[10e0138f1f482b76]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[5f3fca9184d705d1]::plumbing::QueryCtxt, false>
  39:     0x7f51c05253bf - rustc_query_impl[5f3fca9184d705d1]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  40:     0x7f51c0534896 - rustc_interface[94ec20dfe64cdcea]::interface::run_compiler::<core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>, rustc_driver_impl[db1009755931a507]::run_compiler::{closure#0}>::{closure#0}
  41:     0x7f51c07caa4d - std[d1f7731e2ff5974d]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[94ec20dfe64cdcea]::util::run_in_thread_with_globals<rustc_interface[94ec20dfe64cdcea]::util::run_in_thread_pool_with_globals<rustc_interface[94ec20dfe64cdcea]::interface::run_compiler<core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>, rustc_driver_impl[db1009755931a507]::run_compiler::{closure#0}>::{closure#0}, core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>>::{closure#0}, core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>>
  42:     0x7f51c07ca87a - <<std[d1f7731e2ff5974d]::thread::Builder>::spawn_unchecked_<rustc_interface[94ec20dfe64cdcea]::util::run_in_thread_with_globals<rustc_interface[94ec20dfe64cdcea]::util::run_in_thread_pool_with_globals<rustc_interface[94ec20dfe64cdcea]::interface::run_compiler<core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>, rustc_driver_impl[db1009755931a507]::run_compiler::{closure#0}>::{closure#0}, core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>>::{closure#0}, core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[bd87c62ae3a7b4ee]::result::Result<(), rustc_span[6ccc48fe7a4f1f83]::ErrorGuaranteed>>::{closure#1} as core[bd87c62ae3a7b4ee]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  43:     0x7f51bb599725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h11737601996c7bc7
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/alloc/src/boxed.rs:2016:9
  44:     0x7f51bb599725 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb64bc4a2c7899523
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/alloc/src/boxed.rs:2016:9
  45:     0x7f51bb599725 - std::sys::pal::unix::thread::Thread::new::thread_start::h9f6bca54366231ee
                               at /rustc/8f359beca4e58bc3ae795a666301a8f47023044c/library/std/src/sys/pal/unix/thread.rs:108:17
  46:     0x7f51bb38055a - <unknown>
  47:     0x7f51bb3fda3c - <unknown>
  48:                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: rustc 1.78.0-nightly (8f359beca 2024-02-23) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [hir_crate] getting the crate HIR
#1 [hir_attrs] getting HIR owner attributes in ``
#2 [entry_fn] looking up the entry function of a crate
#3 [analysis] running analysis passes on this crate
end of query stack

[matthiaskrgr]

Crashes since #121120 cc @nnethercote

[nnethercote]

For the record: #121120 helped expose a latent bug in AST validation, which #121545 will fix.

[jieyouxu]

Also (probably the same cause):

trait Foo {
    #[doc=hidden]
    fn foo();
}

[matthiaskrgr]

This code now causes unbound memory growth after when trying to print the query stack. after
query stack during panic:

rustc 1.78.0-nightly (7606c1396 2024-03-04)