ICE in rustdoc: `internal error: entered unreachable code`

[jendrikw]

Code

//! docs
//! See [`S`].

mod mymodule {
    mod experiment {
        #![cfg(feature = "unstable-stuff")]
        pub struct S;
    }
    #[cfg(feature = "unstable-stuff")]
    pub use inner::S;
}

pub use mymodule::*;

#[cfg(doc)]
use mymodule::S;

Meta

Happens with 1.65.0-nightly (2befdefdd 2022-08-06) and stable 1.62.1 (e092d0b6b 2022-07-16).

rustc --version --verbose:

rustc 1.65.0-nightly (2befdefdd 2022-08-06)
binary: rustc
commit-hash: 2befdefdda0f2bc5ff93f7f95633c98841409098
commit-date: 2022-08-06
host: x86_64-unknown-linux-gnu
release: 1.65.0-nightly
LLVM version: 14.0.6

Error output

thread 'rustc' panicked at 'internal error: entered unreachable code', compiler/rustc_resolve/src/lib.rs:1920:67
[...]
error: internal compiler error: unexpected panic

Backtrace

   0:     0x7fa5b089dfbd - std::backtrace_rs::backtrace::libunwind::trace::h8e036432725b1c57
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7fa5b089dfbd - std::backtrace_rs::backtrace::trace_unsynchronized::h4f83092254c85869
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fa5b089dfbd - std::sys_common::backtrace::_print_fmt::h9728b5e056a3ece3
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7fa5b089dfbd - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h48bb4bd2928827d2
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7fa5b08f9c4c - core::fmt::write::h909e69a2c24f44cc
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/fmt/mod.rs:1196:17
   5:     0x7fa5b088f731 - std::io::Write::write_fmt::h7f4b8ab8af89e9ef
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/io/mod.rs:1654:15
   6:     0x7fa5b08a0cd5 - std::sys_common::backtrace::_print::hff4838ebf14a2171
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7fa5b08a0cd5 - std::sys_common::backtrace::print::h2499280374189ad9
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7fa5b08a0cd5 - std::panicking::default_hook::{{closure}}::h8b270fc55eeb284e
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/panicking.rs:295:22
   9:     0x7fa5b08a0949 - std::panicking::default_hook::h3217e229d6e9d13c
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/panicking.rs:314:9
  10:     0x7fa5b10e9571 - rustc_driver[b4654d3c4d4292dd]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7fa5b08a14a6 - std::panicking::rust_panic_with_hook::h9acb8048b738d2e0
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/panicking.rs:702:17
  12:     0x7fa5b08a1269 - std::panicking::begin_panic_handler::{{closure}}::h70f3b839526af6dc
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/panicking.rs:586:13
  13:     0x7fa5b089e474 - std::sys_common::backtrace::__rust_end_short_backtrace::h1ecf2cee857fbe0a
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/sys_common/backtrace.rs:138:18
  14:     0x7fa5b08a0fd9 - rust_begin_unwind
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/panicking.rs:584:5
  15:     0x7fa5b0866253 - core::panicking::panic_fmt::h9f8393e7fd56d655
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/panicking.rs:142:14
  16:     0x7fa5b086611d - core::panicking::panic::h021666fc6a0f7b6b
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/core/src/panicking.rs:48:5
  17:     0x7fa5b155183b - <rustc_resolve[5b0ed6050ef3291b]::Resolver>::resolve_rustdoc_path
  18:     0x55f295c4c533 - <rustdoc[68d5cd1422f7df89]::passes::collect_intra_doc_links::early::EarlyDocLinkResolver>::resolve_doc_links_local
  19:     0x55f295c4985c - rustdoc[68d5cd1422f7df89]::passes::collect_intra_doc_links::early::early_resolve_intra_doc_links
  20:     0x55f295c514ec - <rustc_interface[9f664daa3237129]::interface::Compiler>::enter::<rustdoc[68d5cd1422f7df89]::main_options::{closure#0}::{closure#0}, core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>>
  21:     0x55f295db3916 - rustc_span[1d0b4d44d1f53955]::with_source_map::<core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>, rustc_interface[9f664daa3237129]::interface::create_compiler_and_run<core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>, rustdoc[68d5cd1422f7df89]::main_options::{closure#0}>::{closure#1}>
  22:     0x55f295c53904 - rustc_interface[9f664daa3237129]::interface::create_compiler_and_run::<core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>, rustdoc[68d5cd1422f7df89]::main_options::{closure#0}>
  23:     0x55f295acdeb5 - <scoped_tls[ab1554bfb6e7ab15]::ScopedKey<rustc_span[1d0b4d44d1f53955]::SessionGlobals>>::set::<rustdoc[68d5cd1422f7df89]::main_args::{closure#0}, core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>>
  24:     0x55f295c7a2bf - std[8996aeeb2a45fe64]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[9f664daa3237129]::util::run_in_thread_pool_with_globals<rustdoc[68d5cd1422f7df89]::main_args::{closure#0}, core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>>::{closure#0}, core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>>
  25:     0x55f295d1a3f9 - <<std[8996aeeb2a45fe64]::thread::Builder>::spawn_unchecked_<rustc_interface[9f664daa3237129]::util::run_in_thread_pool_with_globals<rustdoc[68d5cd1422f7df89]::main_args::{closure#0}, core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>>::{closure#0}, core[dbea6f494faa966e]::result::Result<(), rustc_errors[4633ef6e4608f9c1]::ErrorGuaranteed>>::{closure#1} as core[dbea6f494faa966e]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  26:     0x7fa5b08ab3c3 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h191d5c5ea3edb31d
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/alloc/src/boxed.rs:1872:9
  27:     0x7fa5b08ab3c3 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h42ef7cb2ae640a31
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/alloc/src/boxed.rs:1872:9
  28:     0x7fa5b08ab3c3 - std::sys::unix::thread::Thread::new::thread_start::he47f7169665dab60
                               at /rustc/e092d0b6b43f2de967af0887873151bb1c0b18d3/library/std/src/sys/unix/thread.rs:108:17
  29:     0x7fa5b059954d - <unknown>
  30:     0x7fa5b061e874 - clone
  31:                0x0 - <unknown>

[petrochenkov]

Fixed in #103096.