rustdoc ICE: entered unreachable code on hidden tuple item

[Emilgardis]

Code

pub enum Foo {
    Test(#[doc(hidden)] Option<()>),
}

panics when running cargo doc. This seems to come from

rust/src/librustdoc/html/render/print_item.rs

Line 943 in ed30993

.map(|f| if let clean::StructFieldItem(ref ty) = *f.kind { ty } else { unreachable!() })

cc #88391

Meta

rustc --version --verbose:

rustc 1.56.0-nightly (50171c310 2021-09-01)
binary: rustc
commit-hash: 50171c310cd15e1b2d3723766ce64e2e4d6696fc
commit-date: 2021-09-01
host: x86_64-pc-windows-msvc
release: 1.56.0-nightly
LLVM version: 13.0.0

Error output

cargo doc --no-deps      
 Documenting hidden v0.1.0-rc.1 (G:\workspace\small dev space\test_crate-version)
thread 'rustc' panicked at 'internal error: entered unreachable code', src\librustdoc\html\render\print_item.rs:943:80
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

error: internal compiler error: unexpected panic

error: Unrecognized option: 'crate-version'

error: could not document `hidden`

Caused by:
  process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name hidden src\lib.rs -o "G:\workspace\small dev space\test_crate-version\target\doc" --error-format=json --json=diagnostic-rendered-ansi -L "dependency=G:\workspace\small dev space\test_crate-version\target\debug\deps" --crate-version 0.1.0-rc.1` (exit code: 1)

Backtrace

thread 'rustc' panicked at 'internal error: entered unreachable code', src\librustdoc\html\render\print_item.rs:943:80
stack backtrace:
   0:     0x7ff80a64801e - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h97844c02df23ebf1
   1:     0x7ff80a6728da - core::fmt::write::h7e004fee938dc3bd
   2:     0x7ff80a63b388 - <std::io::IoSlice as core::fmt::Debug>::fmt::h34e482c524fdd2ee
   3:     0x7ff80a64bab6 - std::panicking::take_hook::hd051283b0b015437
   4:     0x7ff80a64b5c8 - std::panicking::take_hook::hd051283b0b015437
   5:     0x7ff80390ad95 - <md5::Md5 as std::io::Write>::flush::h7054a9d890538508
   6:     0x7ff80a64c3b0 - std::panicking::rust_panic_with_hook::h1dfae7c828339eef
   7:     0x7ff80a64be3f - rust_begin_unwind
   8:     0x7ff80a648947 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h97844c02df23ebf1
   9:     0x7ff80a64bdc9 - rust_begin_unwind
  10:     0x7ff80a6a8980 - core::panicking::panic_fmt::hec18c52ab5ec8c2e
  11:     0x7ff80a6a88cc - core::panicking::panic::h5cccc34aab9ab48d
  12:     0x7ff707957d6c - <unknown>
  13:     0x7ff70794a0b7 - <unknown>
  14:     0x7ff70793c43f - <unknown>
  15:     0x7ff707947276 - <unknown>
  16:     0x7ff707a41406 - <unknown>
  17:     0x7ff70785ede5 - <unknown>
  18:     0x7ff70797661a - <unknown>
  19:     0x7ff70789aab3 - <unknown>
  20:     0x7ff70796e8f4 - <unknown>
  21:     0x7ff70789cf3a - <unknown>
  22:     0x7ff70789363a - <unknown>
  23:     0x7ff7079e6296 - <unknown>
  24:     0x7ff707978de8 - <unknown>
  25:     0x7ff70791d68d - <unknown>
  26:     0x7ff80a65a64c - std::sys::windows::thread::Thread::new::h4e02b30388f9fde7
  27:     0x7ff8dec054e0 - BaseThreadInitThunk
  28:     0x7ff8dfa2485b - RtlUserThreadStart

[jyn514]

@Emilgardis what is that attribute intended to do? Enum fields are always public.

[Emilgardis]

I wanted to hide the field from docs because it was not important. But I agree it's probably a bit strange.