byte index 4 is not a char boundary;

[matthiaskrgr]

//


pub fn main() {}

thread 'main' panicked at src/tools/rustfmt/src/missed_spans.rs:216:36:
byte index 4 is not a char boundary; it is inside '\u{2028}' (bytes 3..6) of `//


`
stack backtrace:
   0:     0x78b846f6d72a - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::h672668bd5fbc6747
   1:     0x78b847613d7c - core::fmt::write::h1c272aa884a4082c
   2:     0x78b848572b51 - std::io::Write::write_fmt::hfd1b0b8c2f046787
   3:     0x78b846f6d582 - std::sys::backtrace::BacktraceLock::print::h4274bb5562f27f33
   4:     0x78b846f6fa7a - std::panicking::default_hook::{{closure}}::h06d790cfc4765386
   5:     0x78b846f6f8c3 - std::panicking::default_hook::hbaba8e6fbddaf0bb
   6:     0x78b8460dc978 - std[1dec83a902989b10]::panicking::update_hook::<alloc[c28ee22c574c43a5]::boxed::Box<rustc_driver_impl[914e6f53ce1bc03e]::install_ice_hook::{closure#0}>>::{closure#0}
   7:     0x78b846f70238 - std::panicking::rust_panic_with_hook::h1df75c095a4f3488
   8:     0x78b846f6ff2a - std::panicking::begin_panic_handler::{{closure}}::hf3afa20cd541c11f
   9:     0x78b846f6dbd9 - std::sys::backtrace::__rust_end_short_backtrace::h3ced788cfddd85e3
  10:     0x78b846f6fbed - rust_begin_unwind
  11:     0x78b843bb1990 - core::panicking::panic_fmt::ha07a50819406191f
  12:     0x78b845b13677 - core::str::slice_error_fail_rt::h94fc6469cd6e8f26
  13:     0x78b845b1333a - core::str::slice_error_fail::hf74663b5ae173cf4
  14:     0x5b05ddbe8f21 - <rustfmt_nightly[e46619801dc48d84]::visitor::FmtVisitor>::format_missing_inner::<<rustfmt_nightly[e46619801dc48d84]::visitor::FmtVisitor>::format_missing_indent::{closure#0}>
  15:     0x5b05ddc1df88 - <rustfmt_nightly[e46619801dc48d84]::visitor::FmtVisitor>::visit_fn
  16:     0x5b05ddc1f2eb - <rustfmt_nightly[e46619801dc48d84]::visitor::FmtVisitor>::visit_item
  17:     0x5b05ddbffab1 - <rustfmt_nightly[e46619801dc48d84]::visitor::FmtVisitor>::visit_items_with_reordering
  18:     0x5b05ddc2ea4b - <rustfmt_nightly[e46619801dc48d84]::visitor::FmtVisitor>::format_separate_mod
  19:     0x5b05dda8825a - <scoped_tls[e196119f2bca9f54]::ScopedKey<rustc_span[1f5f77272f7ff56d]::SessionGlobals>>::with::<<rustfmt_nightly[e46619801dc48d84]::Session<std[1dec83a902989b10]::io::stdio::Stdout>>::format_input_inner::{closure#0}, core[925518ec66bfeb2a]::result::Result<rustfmt_nightly[e46619801dc48d84]::FormatReport, rustfmt_nightly[e46619801dc48d84]::ErrorKind>>
  20:     0x5b05ddaa2e5b - rustfmt[e1dfe25e16623e65]::format_and_emit_report::<std[1dec83a902989b10]::io::stdio::Stdout>
  21:     0x5b05ddaa0a52 - rustfmt[e1dfe25e16623e65]::execute
  22:     0x5b05dda9ca53 - rustfmt[e1dfe25e16623e65]::main
  23:     0x5b05dda90fa3 - std[1dec83a902989b10]::sys::backtrace::__rust_begin_short_backtrace::<fn(), ()>
  24:     0x5b05dda91529 - std[1dec83a902989b10]::rt::lang_start::<()>::{closure#0}
  25:     0x78b8485def58 - std::rt::lang_start_internal::h9084ca16043064bd
  26:     0x5b05ddaa40a8 - main
  27:     0x78b842745e08 - <unknown>
  28:     0x78b842745ecc - __libc_start_main
  29:     0x5b05dda847b9 - <unknown>
  30:                0x0 - <unknown>

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rustfmt/issues/new?labels=bug

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

note: please attach the file at `/tmp/im/rustc-ice-2024-12-19T07_27_18-2727633.txt` to your bug report

query stack during panic:
end of query stack

[matthiaskrgr]

a.rs.txt

[ytmimi]

In the example above, line 2 ends with a Line Separator, and rustfmt fails when it tries to report the trailing whitespace. Pretty sure this is a duplicate of #5876, and I think there's a good chance this will be fixed by #6391

1 | //
2 |

  | ^ line ends with (U+2028)
  |
3 | pub fn main() {}