ICE in rustdoc `redundant_explicit_links` with non-ASCII link text

[kpreid]

Code

Reduced from the source code of bumpalo 3.13.0:

/// [`…foo`] [`…bar`] [`Err`]
pub struct Broken {}

Meta

rustc --version --verbose:

rustc 1.74.0-nightly (5c6a7e71c 2023-08-20)
binary: rustc
commit-hash: 5c6a7e71cd66705c31c9af94077901a220f0870c
commit-date: 2023-08-20
host: x86_64-apple-darwin
release: 1.74.0-nightly
LLVM version: 17.0.0

Error output

thread 'rustc' panicked at src/librustdoc/passes/lint/redundant_explicit_links.rs:105:38:
byte index 2 is not a char boundary; it is inside '…' (bytes 1..4) of ``…foo``

Backtrace

thread 'rustc' panicked at src/librustdoc/passes/lint/redundant_explicit_links.rs:105:38:
byte index 2 is not a char boundary; it is inside '…' (bytes 1..4) of ``…foo``
stack backtrace:
   0:        0x10627bf0b - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h0a889342af22c001
   1:        0x1062dc77b - core::fmt::write::h2a9552489c640d30
   2:        0x10627098e - std::io::Write::write_fmt::h957f1bc49a89c995
   3:        0x10627bce9 - std::sys_common::backtrace::print::hd3ca24f2b09e2d6b
   4:        0x10627f3c8 - std::panicking::panic_hook_with_disk_dump::{{closure}}::hfdbd4926b1318eff
   5:        0x10627f090 - std::panicking::panic_hook_with_disk_dump::hff36df8bfb145345
   6:        0x114f89181 - rustc_driver_impl[271211c656e69f7c]::install_ice_hook::{closure#0}
   7:        0x10627fc10 - std::panicking::rust_panic_with_hook::h3d225d93354d6850
   8:        0x10627f9b3 - std::panicking::begin_panic_handler::{{closure}}::hfb6f37b7f59b8143
   9:        0x10627c3e9 - std::sys_common::backtrace::__rust_end_short_backtrace::h5cb50ae720fa1297
  10:        0x10627f6dd - _rust_begin_unwind
  11:        0x106308023 - core::panicking::panic_fmt::hda3b11d26a2996a0
  12:        0x1062e1595 - core::str::slice_error_fail_rt::hb64c0d7c400011f0
  13:        0x1063087b9 - core::str::slice_error_fail::h4ada315b265e1d30
  14:        0x104865f69 - rustdoc[7e76fc70b3a238cf]::passes::lint::redundant_explicit_links::visit_item
  15:        0x10483b8d7 - <rustdoc[7e76fc70b3a238cf]::passes::lint::Linter as rustdoc[7e76fc70b3a238cf]::visit::DocVisitor>::visit_item
  16:        0x10483b9bc - <rustdoc[7e76fc70b3a238cf]::passes::lint::Linter as rustdoc[7e76fc70b3a238cf]::visit::DocVisitor>::visit_item
  17:        0x10483b3f8 - rustdoc[7e76fc70b3a238cf]::passes::lint::run_lints
  18:        0x10476b05a - <rustc_session[aab8e8868057613]::session::Session>::time::<(rustdoc[7e76fc70b3a238cf]::clean::types::Crate, rustdoc[7e76fc70b3a238cf]::config::RenderOptions, rustdoc[7e76fc70b3a238cf]::formats::cache::Cache), rustdoc[7e76fc70b3a238cf]::main_args::{closure#1}::{closure#0}::{closure#0}::{closure#0}>
  19:        0x10483e03b - <rustc_middle[110db10588286083]::ty::context::GlobalCtxt>::enter::<rustdoc[7e76fc70b3a238cf]::main_args::{closure#1}::{closure#0}::{closure#0}, core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>>
  20:        0x10477001c - <scoped_tls[14d6625b228cefa1]::ScopedKey<rustc_span[3fe5612a2015833b]::SessionGlobals>>::set::<rustc_interface[81a8130e43f77706]::interface::run_compiler<core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>, rustdoc[7e76fc70b3a238cf]::main_args::{closure#1}>::{closure#0}, core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>>
  21:        0x1049f9df3 - std[8dadf9e2e2548a40]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[81a8130e43f77706]::util::run_in_thread_pool_with_globals<rustc_interface[81a8130e43f77706]::interface::run_compiler<core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>, rustdoc[7e76fc70b3a238cf]::main_args::{closure#1}>::{closure#0}, core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>>
  22:        0x1049fa56e - <<std[8dadf9e2e2548a40]::thread::Builder>::spawn_unchecked_<rustc_interface[81a8130e43f77706]::util::run_in_thread_pool_with_globals<rustc_interface[81a8130e43f77706]::interface::run_compiler<core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>, rustdoc[7e76fc70b3a238cf]::main_args::{closure#1}>::{closure#0}, core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[cee64f789374d93]::result::Result<(), rustc_span[3fe5612a2015833b]::ErrorGuaranteed>>::{closure#1} as core[cee64f789374d93]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  23:        0x106289949 - std::sys::unix::thread::Thread::new::thread_start::h4626e4e0af234279
  24:     0x7ff817d4b4e1 - __pthread_start


rustc version: 1.74.0-nightly (5c6a7e71c 2023-08-20)
platform: x86_64-apple-darwin

query stack during panic:
end of query stack

Other notes

Would have been introduced by #113167 since that PR added the lint.. cc @ChAoSUnItY

@rustbot label -T-compiler +T-rustdoc