[ICE]: When running rustdoc

[ilovepi]

Code

crate_a.rs

pub struct Item<B>(pub B);

pub struct Container<B>(pub B);

impl<B> Container<B> {
    pub fn get_item(&self) -> Result<Item<impl Default + std::fmt::Debug + PartialEq + '_>, ()> {
        Ok(Item(0))
    }
}

crate_b.rs

extern crate crate_a;
pub use crate_a::*;

run.sh

#!/usr/bin/env bash
set -e

RUSTC="rustc"
RUSTDOC="rustdoc"

TMP_DIR="$(mktemp -d -t rustdoc_repro_XXXXXX)"

$RUSTC --crate-type=rlib --crate-name=crate_a crate_a.rs -Cmetadata=meta_a -o "$TMP_DIR/libcrate_a.rlib"

$RUSTDOC crate_b.rs \
  --crate-type=rlib \
  --crate-name=crate_a \
  -Cmetadata=meta_b \
  --extern=crate_a="$TMP_DIR/libcrate_a.rlib" \
  --out-dir="$TMP_DIR/doc"

rustc-ice-2026-07-28T23_15_14-1510933.txt

Meta

rustc --version --verbose:

rustdoc --version --verbose
rustdoc 1.98.0-nightly (c55fad5a9 2026-06-18)
binary: rustdoc
commit-hash: c55fad5a9048ad0f7cff2a4867a297647af9392b
commit-date: 2026-06-18
host: x86_64-unknown-linux-gnu
release: 1.98.0-nightly
LLVM version: 23.0.0

Error output

thread 'rustc' (1510934) panicked at compiler/rustc_metadata/src/rmeta/decoder.rs:1398:17:
assertion `left == right` failed
  left: OpaqueTy
 right: Ctor
stack backtrace:
   0:     0x7f612813bdf8 - std[ab53626fa230f38a]::backtrace_rs::backtrace::libunwind::trace
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/../../backtrace/src/backtrace/libunwind.rs:117:9
   1:     0x7f612813bdf8 - std[ab53626fa230f38a]::backtrace_rs::backtrace::trace_unsynchronized::<std[ab53626fa230f38a]::sys::backtrace::_print_fmt::{closure#1}>
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/../../backtrace/src/backtrace/mod.rs:66:14
   2:     0x7f612813bdf8 - std[ab53626fa230f38a]::sys::backtrace::_print_fmt
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/sys/backtrace.rs:74:9
   3:     0x7f612813bdf8 - <<std[ab53626fa230f38a]::sys::backtrace::BacktraceLock>::print::DisplayBacktrace as core[ee11899e83b1d2d7]::fmt::Display>::fmt
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/sys/backtrace.rs:44:26
   4:     0x7f6122a8bf3a - <core[ee11899e83b1d2d7]::fmt::rt::Argument>::fmt
                               at /b/s/w/ir/x/w/rust-rust/library/core/src/fmt/rt.rs:152:76
   5:     0x7f6122a8bf3a - core[ee11899e83b1d2d7]::fmt::write
   6:     0x7f612814cad2 - std[ab53626fa230f38a]::io::default_write_fmt::<std[ab53626fa230f38a]::sys::stdio::unix::Stderr>
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/io/mod.rs:623:11
   7:     0x7f612814cad2 - <std[ab53626fa230f38a]::sys::stdio::unix::Stderr as std[ab53626fa230f38a]::io::Write>::write_fmt
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/io/mod.rs:1727:13
   8:     0x7f612810f7f6 - <std[ab53626fa230f38a]::sys::backtrace::BacktraceLock>::print
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/sys/backtrace.rs:47:9
   9:     0x7f612810f7f6 - std[ab53626fa230f38a]::panicking::default_hook::{closure#0}
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/panicking.rs:292:27
  10:     0x7f612812ee41 - std[ab53626fa230f38a]::panicking::default_hook
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/panicking.rs:319:9
  11:     0x7f61236529fd - std[ab53626fa230f38a]::panicking::update_hook::<alloc[c1b2569c24cfe1a1]::boxed::Box<rustc_driver_impl[1ab504540eac0b3b]::install_ice_hook::{closure#1}>>::{closure#0}
  12:     0x7f612812f0f2 - <alloc[c1b2569c24cfe1a1]::boxed::Box<dyn for<'a, 'b> core[ee11899e83b1d2d7]::ops::function::Fn<(&'a std[ab53626fa230f38a]::panic::PanicHookInfo<'b>,), Output = ()> + core[ee11899e83b1d2d7]::marker::Sync + core[ee11899e83b1d2d7]::marker::Send> as core[ee11899e83b1d2d7]::ops::function::Fn<(&std[ab53626fa230f38a]::panic::PanicHookInfo,)>>::call
                               at /b/s/w/ir/x/w/rust-rust/library/alloc/src/boxed.rs:2287:9
  13:     0x7f612812f0f2 - std[ab53626fa230f38a]::panicking::panic_with_hook
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/panicking.rs:822:13
  14:     0x7f612810f8b2 - std[ab53626fa230f38a]::panicking::panic_handler::{closure#0}
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/panicking.rs:687:13
  15:     0x7f6128105ed9 - std[ab53626fa230f38a]::sys::backtrace::__rust_end_short_backtrace::<std[ab53626fa230f38a]::panicking::panic_handler::{closure#0}, !>
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/sys/backtrace.rs:182:18
  16:     0x7f6128110f8d - __rustc[f2d0d3bbd64a86a8]::rust_begin_unwind
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/panicking.rs:678:5
  17:     0x7f6122d6683c - core[ee11899e83b1d2d7]::panicking::panic_fmt
                               at /b/s/w/ir/x/w/rust-rust/library/core/src/panicking.rs:80:14
  18:     0x7f6128183093 - core[ee11899e83b1d2d7]::panicking::assert_failed_inner
                               at /b/s/w/ir/x/w/rust-rust/library/core/src/panicking.rs:439:17
  19:     0x7f6127935f0f - core[ee11899e83b1d2d7]::panicking::assert_failed::<rustc_hir[a6df33731b7cde54]::definitions::DefPathData, rustc_hir[a6df33731b7cde54]::definitions::DefPathData>
  20:     0x7f6122d2e954 - rustc_metadata[f4e2fa3d801d9e0]::rmeta::decoder::cstore_impl::provide_extern::attrs_for_def
  21:     0x7f61229674a0 - rustc_query_impl[ab30a29e4c3081f]::query_impl::attrs_for_def::invoke_provider_fn::__rust_begin_short_backtrace
  22:     0x7f6122965d5d - rustc_query_impl[ab30a29e4c3081f]::execution::try_execute_query::<rustc_middle[12ea5071f0106e6f]::query::caches::DefIdCache<rustc_middle[12ea5071f0106e6f]::query::erase::ErasedData<[u8; 16usize]>>, false>
  23:     0x7f6122965915 - rustc_query_impl[ab30a29e4c3081f]::query_impl::attrs_for_def::execute_query_non_incr::__rust_end_short_backtrace
  24:     0x7f612305d59e - <rustc_span[37f735d4c01bddd0]::def_id::DefId as rustc_hir[a6df33731b7cde54]::attrs::HasAttrs<rustc_middle[12ea5071f0106e6f]::ty::context::TyCtxt>>::get_attrs
  25:     0x558ec3319855 - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index::convert_render_type_id
  26:     0x558ec331965e - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index::convert_render_type
  27:     0x558ec3319385 - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index::convert_render_type
  28:     0x558ec3319385 - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index::convert_render_type
  29:     0x558ec3319385 - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index::convert_render_type
  30:     0x558ec3319385 - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index::convert_render_type
  31:     0x558ec32fcf78 - rustdoc[a6367163f4ab8a8f]::html::render::search_index::build_index
  32:     0x558ec3302a10 - rustdoc[a6367163f4ab8a8f]::html::render::write_shared::write_shared
  33:     0x558ec325226d - <rustdoc[a6367163f4ab8a8f]::html::render::context::Context>::init
  34:     0x558ec31cd270 - rustdoc[a6367163f4ab8a8f]::main_args::{closure#2}::{closure#0}
  35:     0x558ec31c1c04 - rustc_interface[e5a84faf1e80c17e]::interface::run_compiler::<(), rustdoc[a6367163f4ab8a8f]::main_args::{closure#2}>::{closure#1}
  36:     0x558ec310cb96 - std[ab53626fa230f38a]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[e5a84faf1e80c17e]::util::run_in_thread_with_globals<rustc_interface[e5a84faf1e80c17e]::util::run_in_thread_pool_with_globals<rustc_interface[e5a84faf1e80c17e]::interface::run_compiler<(), rustdoc[a6367163f4ab8a8f]::main_args::{closure#2}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>
  37:     0x558ec31fed6d - <std[ab53626fa230f38a]::thread::lifecycle::spawn_unchecked<rustc_interface[e5a84faf1e80c17e]::util::run_in_thread_with_globals<rustc_interface[e5a84faf1e80c17e]::util::run_in_thread_pool_with_globals<rustc_interface[e5a84faf1e80c17e]::interface::run_compiler<(), rustdoc[a6367163f4ab8a8f]::main_args::{closure#2}>::{closure#1}, ()>::{closure#0}, ()>::{closure#0}::{closure#0}, ()>::{closure#1} as core[ee11899e83b1d2d7]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  38:     0x7f612813920f - <alloc[c1b2569c24cfe1a1]::boxed::Box<dyn core[ee11899e83b1d2d7]::ops::function::FnOnce<(), Output = ()> + core[ee11899e83b1d2d7]::marker::Send> as core[ee11899e83b1d2d7]::ops::function::FnOnce<()>>::call_once
                               at /b/s/w/ir/x/w/rust-rust/library/alloc/src/boxed.rs:2273:9
  39:     0x7f612813920f - <std[ab53626fa230f38a]::sys::thread::unix::Thread>::new::thread_start
                               at /b/s/w/ir/x/w/rust-rust/library/std/src/sys/thread/unix.rs:118:17
  40:     0x7f611f89de69 - start_thread
                               at ./nptl/pthread_create.c:448:8
  41:     0x7f611f91ce48 - __GI___clone3
                               at /build/reproducible-path/glibc-2.42/misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78:0

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-rustdoc&template=ice.md

note: please make sure that you have updated to the latest nightly

note: please attach the file at `/usr/local/google/home/paulkirth/fuchsia/repro/rustc-ice-2026-07-28T23_15_14-1510933.txt` to your bug report

note: rustc 1.98.0-nightly (c55fad5a9 2026-06-18) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type rlib

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [attrs_for_def] collecting attributes of `crate_a::Container<B>::get_item::{opaque#0}`
end of query stack

We ran into this in Fuchsia (https://fxbug.dev/539676977), and I was able to minimize the case down to something very small. I haven't looked closely as to why this happens. I suspect something about the crate name, but I'm not really sure, as I'm not too familiar with rmeta lookups or rustdoc internals. In any case, this feels like something that shouldn't panic or crash the tool, even if its in some bad or invalid state.

[theemathas]

This looks like a duplicate of #158686, which is fixed on the latest nightly.

[theemathas]

Except... it's not a duplicate, because I can reproduce this on rustdoc 1.99.0-nightly (09ee43b2d 2026-07-27) and also on rustdoc 1.98.0-beta.6 (0c45ca314 2026-07-25)

[theemathas]

It also reproduces on 1.97.0. I'm currently having trouble installing older versions of rust to test or bisect this, but I'm going to assume for now that it's a stable-to-stable regression.

[apiraino]

I've run a basic bisection and the ICE starts with rust 1.84.0 (until 1.83.0 it compiles)

[apiraino]

A bit more precise bisection:

********************************************************************************
Regression in nightly-2024-11-12
********************************************************************************

looking for regression commit between 2024-11-11 and 2024-11-12
fetching (via remote github) commits from max(143ce0920a2307b19831160a01f06f107610f1b2, 2024-11-09) to 81eef2d362a6f03db6f8928f82d94298d31eb81b
ending github query because we found starting sha: 143ce0920a2307b19831160a01f06f107610f1b2
get_commits_between returning commits, len: 8
  commit[0] 2024-11-10: Auto merge of #132877 - matthiaskrgr:rollup-hbxg7p0, r=matthiaskrgr
  commit[1] 2024-11-11: Auto merge of #126597 - estebank:unicode-output, r=fmease
  commit[2] 2024-11-11: Auto merge of #132885 - jhpratt:rollup-4ddd31p, r=jhpratt
  commit[3] 2024-11-11: Auto merge of #132854 - RalfJung:query-key-limit, r=compiler-errors
  commit[4] 2024-11-11: Auto merge of #132880 - RalfJung:implied-features, r=workingjubilee
  commit[5] 2024-11-11: Auto merge of #127589 - notriddle:notriddle/search-sem-3, r=GuillaumeGomez
  commit[6] 2024-11-11: Auto merge of #132720 - jieyouxu:do-not-strip, r=davidtwco
  commit[7] 2024-11-11: Auto merge of #132902 - matthiaskrgr:rollup-43qgg3t, r=matthiaskrgr
ERROR: no CI builds available between 143ce0920a2307b19831160a01f06f107610f1b2 and 81eef2d362a6f03db6f8928f82d94298d31eb81b within last 167 days