ICE: `elem.index() < self.domain_size`

[matthiaskrgr]

auto-reduced (treereduce-rust):

enum NestedEnum {
    First,
    Second,
    Third
}
enum Enum {
    Variant2(Option<*mut &'a &'b ()>)
}


fn foo(x: Enum) -> isize {
    match x {
      Enum::Variant2(NestedEnum::Third) => 4,  
    }
}

original:

#![allow(dead_code)]

enum NestedEnum {
    First,
    Second,
    Third
}
enum Enum {
    Variant1(bool),
    Variant2(Option<*mut &'a &'b ()>)
}

#[inline(never)]
fn foo(x: Enum) -> isize {
    match x {
        Enum::Variant1(true) => 1,
        Enum::Variant1(false) => 2,
        Enum::Variant2(NestedEnum::Second) => 3,
        Enum::Variant2(NestedEnum::Third) => 4,
        Enum::Variant2(NestedEnum::First) => 5
    }
}

fn main() {
    assert_eq!(foo(Enum::Variant2(NestedEnum::Third)), 4);
}

Version information

rustc 1.80.0-nightly (9e7aff794 2024-05-15)
binary: rustc
commit-hash: 9e7aff794539aa040362f4424eb29207449ffce0
commit-date: 2024-05-15
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.4

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc

Program output

error: expected identifier, found `,`
 --> /tmp/icemaker_global_tempdir.atr7tKB0tvNE/rustc_testrunner_tmpdir_reporting.a4Uxzxxnly6f/mvce.rs:9:5
  |
9 |     ,
  |     ^
  |     |
  |     expected identifier
  |     help: remove this comma

error[E0261]: use of undeclared lifetime name `'a`
  --> /tmp/icemaker_global_tempdir.atr7tKB0tvNE/rustc_testrunner_tmpdir_reporting.a4Uxzxxnly6f/mvce.rs:10:27
   |
8  | enum Enum {
   |          - help: consider introducing lifetime `'a` here: `<'a>`
9  |     ,
10 |     Variant2(Option<*mut &'a &'b ()>)
   |                           ^^ undeclared lifetime

error[E0261]: use of undeclared lifetime name `'b`
  --> /tmp/icemaker_global_tempdir.atr7tKB0tvNE/rustc_testrunner_tmpdir_reporting.a4Uxzxxnly6f/mvce.rs:10:31
   |
8  | enum Enum {
   |          - help: consider introducing lifetime `'b` here: `<'b>`
9  |     ,
10 |     Variant2(Option<*mut &'a &'b ()>)
   |                               ^^ undeclared lifetime

error[E0601]: `main` function not found in crate `mvce`
  --> /tmp/icemaker_global_tempdir.atr7tKB0tvNE/rustc_testrunner_tmpdir_reporting.a4Uxzxxnly6f/mvce.rs:22:2
   |
22 | }
   |  ^ consider adding a `main` function to `/tmp/icemaker_global_tempdir.atr7tKB0tvNE/rustc_testrunner_tmpdir_reporting.a4Uxzxxnly6f/mvce.rs`

thread 'rustc' panicked at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/compiler/rustc_index/src/bit_set.rs:188:9:
assertion failed: elem.index() < self.domain_size
stack backtrace:
   0:     0x7507130fee55 - std::backtrace_rs::backtrace::libunwind::trace::hc82148572bca43ce
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7507130fee55 - std::backtrace_rs::backtrace::trace_unsynchronized::h9b6c0021060334e8
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7507130fee55 - std::sys_common::backtrace::_print_fmt::hdf50e160c2606d9a
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7507130fee55 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hd89105eb919743fa
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x75071314e16b - core::fmt::rt::Argument::fmt::h299039627f9699b8
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/core/src/fmt/rt.rs:165:63
   5:     0x75071314e16b - core::fmt::write::h90d4bcf0308a6921
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/core/src/fmt/mod.rs:1169:21
   6:     0x7507130f3b3f - std::io::Write::write_fmt::h971d4bf5135c0400
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/io/mod.rs:1835:15
   7:     0x7507130fec2e - std::sys_common::backtrace::_print::h0249ba9e007e0890
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7507130fec2e - std::sys_common::backtrace::print::h512af02446eaf912
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x750713101649 - std::panicking::default_hook::{{closure}}::hd7eed3dbeb3b0e1b
  10:     0x75071310138d - std::panicking::default_hook::hc22637f42e887b27
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/panicking.rs:298:9
  11:     0x75070faf4d5f - std[e1f444a3457101b2]::panicking::update_hook::<alloc[dde3ecb08ca6e715]::boxed::Box<rustc_driver_impl[5e1c2d2058911521]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x750713101d7b - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h53851f315593fb6e
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/alloc/src/boxed.rs:2036:9
  13:     0x750713101d7b - std::panicking::rust_panic_with_hook::h5e0b74345c48df96
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/panicking.rs:799:13
  14:     0x750713101abb - std::panicking::begin_panic_handler::{{closure}}::h35a2f90e39b3450a
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/panicking.rs:656:13
  15:     0x7507130ff319 - std::sys_common::backtrace::__rust_end_short_backtrace::hc74b426b89ea2072
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x750713101827 - rust_begin_unwind
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/panicking.rs:652:5
  17:     0x75071314a733 - core::panicking::panic_fmt::h64193357920b31af
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/core/src/panicking.rs:72:14
  18:     0x75071314a7dc - core::panicking::panic::hd8eed21f3f9250e7
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/core/src/panicking.rs:146:5
  19:     0x750711533c1b - rustc_pattern_analysis[51b46f04f23eb7fd]::usefulness::compute_exhaustiveness_and_usefulness::<rustc_pattern_analysis[51b46f04f23eb7fd]::rustc::RustcPatCtxt>::{closure#0}
  20:     0x75071152f314 - rustc_pattern_analysis[51b46f04f23eb7fd]::usefulness::compute_exhaustiveness_and_usefulness::<rustc_pattern_analysis[51b46f04f23eb7fd]::rustc::RustcPatCtxt>::{closure#0}
  21:     0x75071153da54 - rustc_pattern_analysis[51b46f04f23eb7fd]::analyze_match
  22:     0x75070e3d5869 - <rustc_mir_build[36a8aa01da2a74cf]::thir::pattern::check_match::MatchVisitor as rustc_middle[2ad1b0c79c7e2a2b]::thir::visit::Visitor>::visit_expr
  23:     0x75070e3d4d8d - <rustc_mir_build[36a8aa01da2a74cf]::thir::pattern::check_match::MatchVisitor as rustc_middle[2ad1b0c79c7e2a2b]::thir::visit::Visitor>::visit_expr
  24:     0x75070e3d5c64 - <rustc_mir_build[36a8aa01da2a74cf]::thir::pattern::check_match::MatchVisitor as rustc_middle[2ad1b0c79c7e2a2b]::thir::visit::Visitor>::visit_expr
  25:     0x75070e3d4d8d - <rustc_mir_build[36a8aa01da2a74cf]::thir::pattern::check_match::MatchVisitor as rustc_middle[2ad1b0c79c7e2a2b]::thir::visit::Visitor>::visit_expr
  26:     0x75071114470c - rustc_mir_build[36a8aa01da2a74cf]::thir::pattern::check_match::check_match
  27:     0x7507111442df - rustc_query_impl[e4f4655505b9e0b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e4f4655505b9e0b]::query_impl::check_match::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 1usize]>>
  28:     0x750711142387 - rustc_query_system[3dc3927fb89859b0]::query::plumbing::try_execute_query::<rustc_query_impl[e4f4655505b9e0b]::DynamicConfig<rustc_query_system[3dc3927fb89859b0]::query::caches::VecCache<rustc_span[22bf4ef945b61209]::def_id::LocalDefId, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[e4f4655505b9e0b]::plumbing::QueryCtxt, false>
  29:     0x750711142015 - rustc_query_impl[e4f4655505b9e0b]::query_impl::check_match::get_query_non_incr::__rust_end_short_backtrace
  30:     0x75071114d5cb - rustc_mir_build[36a8aa01da2a74cf]::build::mir_build
  31:     0x75071114cc8e - rustc_query_impl[e4f4655505b9e0b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e4f4655505b9e0b]::query_impl::mir_built::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 8usize]>>
  32:     0x7507115511f1 - rustc_query_system[3dc3927fb89859b0]::query::plumbing::try_execute_query::<rustc_query_impl[e4f4655505b9e0b]::DynamicConfig<rustc_query_system[3dc3927fb89859b0]::query::caches::VecCache<rustc_span[22bf4ef945b61209]::def_id::LocalDefId, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[e4f4655505b9e0b]::plumbing::QueryCtxt, false>
  33:     0x750711550d0c - rustc_query_impl[e4f4655505b9e0b]::query_impl::mir_built::get_query_non_incr::__rust_end_short_backtrace
  34:     0x75071113e5dc - rustc_mir_build[36a8aa01da2a74cf]::check_unsafety::check_unsafety
  35:     0x75071113e36f - rustc_query_impl[e4f4655505b9e0b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e4f4655505b9e0b]::query_impl::check_unsafety::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 0usize]>>
  36:     0x75071113d3dd - rustc_query_system[3dc3927fb89859b0]::query::plumbing::try_execute_query::<rustc_query_impl[e4f4655505b9e0b]::DynamicConfig<rustc_query_system[3dc3927fb89859b0]::query::caches::VecCache<rustc_span[22bf4ef945b61209]::def_id::LocalDefId, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[e4f4655505b9e0b]::plumbing::QueryCtxt, false>
  37:     0x75071113d097 - rustc_query_impl[e4f4655505b9e0b]::query_impl::check_unsafety::get_query_non_incr::__rust_end_short_backtrace
  38:     0x75071199a31b - rustc_interface[bf6b16ed275f9a93]::passes::analysis
  39:     0x75071199941b - rustc_query_impl[e4f4655505b9e0b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[e4f4655505b9e0b]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 1usize]>>
  40:     0x750711baef65 - rustc_query_system[3dc3927fb89859b0]::query::plumbing::try_execute_query::<rustc_query_impl[e4f4655505b9e0b]::DynamicConfig<rustc_query_system[3dc3927fb89859b0]::query::caches::SingleCache<rustc_middle[2ad1b0c79c7e2a2b]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[e4f4655505b9e0b]::plumbing::QueryCtxt, false>
  41:     0x750711baecc9 - rustc_query_impl[e4f4655505b9e0b]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  42:     0x750711a33e8e - rustc_interface[bf6b16ed275f9a93]::interface::run_compiler::<core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>, rustc_driver_impl[5e1c2d2058911521]::run_compiler::{closure#0}>::{closure#1}
  43:     0x750711a1f4c9 - std[e1f444a3457101b2]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[bf6b16ed275f9a93]::util::run_in_thread_with_globals<rustc_interface[bf6b16ed275f9a93]::util::run_in_thread_pool_with_globals<rustc_interface[bf6b16ed275f9a93]::interface::run_compiler<core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>, rustc_driver_impl[5e1c2d2058911521]::run_compiler::{closure#0}>::{closure#1}, core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>>::{closure#0}, core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>>
  44:     0x750711a1f276 - <<std[e1f444a3457101b2]::thread::Builder>::spawn_unchecked_<rustc_interface[bf6b16ed275f9a93]::util::run_in_thread_with_globals<rustc_interface[bf6b16ed275f9a93]::util::run_in_thread_pool_with_globals<rustc_interface[bf6b16ed275f9a93]::interface::run_compiler<core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>, rustc_driver_impl[5e1c2d2058911521]::run_compiler::{closure#0}>::{closure#1}, core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>>::{closure#0}, core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[621fd6879f29e550]::result::Result<(), rustc_span[22bf4ef945b61209]::ErrorGuaranteed>>::{closure#2} as core[621fd6879f29e550]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  45:     0x75071310bc1b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h3f48e858c823da76
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/alloc/src/boxed.rs:2022:9
  46:     0x75071310bc1b - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he41c381165ad67aa
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/alloc/src/boxed.rs:2022:9
  47:     0x75071310bc1b - std::sys::pal::unix::thread::Thread::new::thread_start::hed17c0eaf3bcb9d0
                               at /rustc/9e7aff794539aa040362f4424eb29207449ffce0/library/std/src/sys/pal/unix/thread.rs:108:17
  48:     0x75070c8a955a - <unknown>
  49:     0x75070c926a3c - <unknown>
  50:                0x0 - <unknown>

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

note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

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

note: rustc 1.80.0-nightly (9e7aff794 2024-05-15) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [check_match] match-checking `foo`
#1 [mir_built] building MIR for `foo`
end of query stack
error: aborting due to 4 previous errors

Some errors have detailed explanations: E0261, E0601.
For more information about an error, try `rustc --explain E0261`.

[matthiaskrgr]

bisects to #122749

[theemathas]

Minimized (kinda):

enum NestedEnum {
    First,
    Second
}

enum Wrap<'a> {
    Wrapped(&'a ())
}

struct Thing(Wrap<'a>);

fn foo(x: Thing) {
    match x {
        Thing(NestedEnum::Second) => {},  
    }
}

The ICE occurs only when the match arm pattern uses the nth variant of NestedEnum, where n is greater than the number of variants in Wrap.