ICE: rustdoc lib: violation of UTF-8 char boundary

[marcospb19]

Command

$ cargo doc

Code

fn main() {}

Cargo.toml:

[package]
name = "example-name"
version = "0.0.0"
edition = "2021"

[dependencies]
axum = "=0.6.20"

It doesn't panic with any crate, but specifically with axum.

Meta

rustc --version --verbose:

rustc 1.74.0-nightly (c469197b1 2023-08-22)
binary: rustc
commit-hash: c469197b19d53a6c45378568f73c00986b20a5a5
commit-date: 2023-08-22
host: x86_64-unknown-linux-gnu
release: 1.74.0-nightly
LLVM version: 17.0.0

Error output

thread 'rustc' panicked at src/librustdoc/passes/collect_intra_doc_links.rs:1446:33:
byte index 2 is not a char boundary; it is inside '“' (bytes 0..3) of `“extractors”`
stack backtrace:
   0:     0x7fd6c0b630fc - std::backtrace_rs::backtrace::libunwind::trace::h05dcd57d35354e09
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7fd6c0b630fc - std::backtrace_rs::backtrace::trace_unsynchronized::h760cef756255b640
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fd6c0b630fc - std::sys_common::backtrace::_print_fmt::h96ee9c0f36e8a7ef
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/sys_common/backtrace.rs:67:5
   3:     0x7fd6c0b630fc - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h79540d81556adb82
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7fd6c0bc93bc - core::fmt::rt::Argument::fmt::h29465cb5b004890a
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/core/src/fmt/rt.rs:138:9
   5:     0x7fd6c0bc93bc - core::fmt::write::hdd9d58a2540bd20b
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/core/src/fmt/mod.rs:1094:21
   6:     0x7fd6c0b55c1e - std::io::Write::write_fmt::h961ffc893f831cdd
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/io/mod.rs:1714:15
   7:     0x7fd6c0b62ee4 - std::sys_common::backtrace::_print::hf69e02dd8b1274ec
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7fd6c0b62ee4 - std::sys_common::backtrace::print::hac9c9d49c3cce28f
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7fd6c0b65fda - std::panicking::panic_hook_with_disk_dump::{{closure}}::hf463d7099ec26505
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/panicking.rs:278:22
  10:     0x7fd6c0b65c89 - std::panicking::panic_hook_with_disk_dump::he6e047f25fe029c3
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/panicking.rs:305:9
  11:     0x7fd6c3d155c9 - <rustc_driver_impl[d555860e81f7517b]::install_ice_hook::{closure#0} as core[b361c132967a94b5]::ops::function::FnOnce<(&core[b361c132967a94b5]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  12:     0x7fd6c0b66880 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h92e08cea9685c71d
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/alloc/src/boxed.rs:2021:9
  13:     0x7fd6c0b66880 - std::panicking::rust_panic_with_hook::h816b3d294e59b8e2
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/panicking.rs:733:13
  14:     0x7fd6c0b66607 - std::panicking::begin_panic_handler::{{closure}}::hf7166c733cbf5800
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/panicking.rs:621:13
  15:     0x7fd6c0b63626 - std::sys_common::backtrace::__rust_end_short_backtrace::h8e9dc421bd779484
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/sys_common/backtrace.rs:170:18
  16:     0x7fd6c0b66352 - rust_begin_unwind
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/panicking.rs:617:5
  17:     0x7fd6c0bc57c3 - core::panicking::panic_fmt::h241ae686aabc346b
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/core/src/panicking.rs:67:14
  18:     0x7fd6c0bce41a - core::str::slice_error_fail_rt::h0a25a5762ae30385
  19:     0x7fd6c0bce227 - core::str::slice_error_fail::ha66e4d5bb6c797a8
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/core/src/str/mod.rs:87:9
  20:     0x556ba94439c5 - <rustdoc[2dcce2dbf46f6921]::passes::collect_intra_doc_links::LinkCollector>::resolve_links
  21:     0x556ba943060d - rustdoc[2dcce2dbf46f6921]::passes::collect_intra_doc_links::collect_intra_doc_links
  22:     0x556ba96684c8 - <rustc_session[3a994007c5c0178c]::session::Session>::time::<(rustdoc[2dcce2dbf46f6921]::clean::types::Crate, rustdoc[2dcce2dbf46f6921]::config::RenderOptions, rustdoc[2dcce2dbf46f6921]::formats::cache::Cache), rustdoc[2dcce2dbf46f6921]::main_args::{closure#1}::{closure#0}::{closure#0}::{closure#0}>
  23:     0x556ba9549632 - <rustc_middle[dc00279793427bd1]::ty::context::GlobalCtxt>::enter::<rustdoc[2dcce2dbf46f6921]::main_args::{closure#1}::{closure#0}::{closure#0}, core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>>
  24:     0x556ba966bccc - <scoped_tls[2eaa6cc3c350de3d]::ScopedKey<rustc_span[695785c96b1568a1]::SessionGlobals>>::set::<rustc_interface[4e5594fb201fb041]::interface::run_compiler<core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>, rustdoc[2dcce2dbf46f6921]::main_args::{closure#1}>::{closure#0}, core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>>
  25:     0x556ba9451349 - std[2ba130f3e4ff0dbf]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[4e5594fb201fb041]::util::run_in_thread_pool_with_globals<rustc_interface[4e5594fb201fb041]::interface::run_compiler<core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>, rustdoc[2dcce2dbf46f6921]::main_args::{closure#1}>::{closure#0}, core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>>
  26:     0x556ba969ad6b - <<std[2ba130f3e4ff0dbf]::thread::Builder>::spawn_unchecked_<rustc_interface[4e5594fb201fb041]::util::run_in_thread_pool_with_globals<rustc_interface[4e5594fb201fb041]::interface::run_compiler<core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>, rustdoc[2dcce2dbf46f6921]::main_args::{closure#1}>::{closure#0}, core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[b361c132967a94b5]::result::Result<(), rustc_span[695785c96b1568a1]::ErrorGuaranteed>>::{closure#1} as core[b361c132967a94b5]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  27:     0x7fd6c0b711e5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hc8312914ab53fd6a
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/alloc/src/boxed.rs:2007:9
  28:     0x7fd6c0b711e5 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h926e053874820907
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/alloc/src/boxed.rs:2007:9
  29:     0x7fd6c0b711e5 - std::sys::unix::thread::Thread::new::thread_start::h615369ddd41aad9b
                               at /rustc/c469197b19d53a6c45378568f73c00986b20a5a5/library/std/src/sys/unix/thread.rs:108:17
  30:     0x7fd6c068c9eb - <unknown>
  31:     0x7fd6c0710dfc - <unknown>
  32:                0x0 - <unknown>


rustc version: 1.74.0-nightly (c469197b1 2023-08-22)
platform: x86_64-unknown-linux-gnu

query stack during panic:
end of query stack

[leikang123]

The error message you provided indicates a panic in the Rust compiler (rustc). The panic occurred in the file collect_intra_doc_links.rs at line 1446, column 33. It seems that there is an issue with byte indexing and character boundaries.
Specifically, the byte at index 2 is not a valid character boundary within the string '“extractors”'. The bytes 0 to 3 correspond to the opening double quotation mark (“). It appears that the indexing operation is trying to access a character starting at an invalid byte index.
o resolve this issue, you might need to inspect the code around line 1446 of the collect_intra_doc_links.rs file. Look for any operations that involve indexing or slicing strings and ensure that they are using valid character boundaries. It's possible that there is an off-by-one error or incorrect handling of Unicode characters.
If you're not the developer of the Rust code itself and you encountered this error while using a Rust library or application, you should consider reporting the issue to the project maintainers. They will be better equipped to investigate and resolve the problem.

[fmease]

Very likely fixed on the latest nightly (by #115070). Can you double-check that? If so, it's a duplicate of #115064, #115062 and #115116.

@rustbot label -needs-triage -T-compiler T-rustdoc

@leikang123 Please refrain from posting ChatGPT-generated responses, they are not productive.

[marcospb19]

Thanks @fmease, indeed fixed by #115070.