ICE: Unexpected type for 'Ref' constructor: *const &'{erased} ()

[matthiaskrgr]

snippet:

struct Outest(*const &'a ());

fn make() -> Outest {}

fn main() {
    if let Outest("foo") = make() {}
}

Version information

rustc 1.81.0-nightly (dd104ef16 2024-06-18)
binary: rustc
commit-hash: dd104ef16315e2387fe94e8c43eb5a66e3dbd660
commit-date: 2024-06-18
host: x86_64-unknown-linux-gnu
release: 1.81.0-nightly
LLVM version: 18.1.7

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

Program output

error[E0261]: use of undeclared lifetime name `'a`
 --> /tmp/icemaker_global_tempdir.TgpW6JrktGaA/rustc_testrunner_tmpdir_reporting.7eRm4vVFAtEm/mvce.rs:1:23
  |
1 | struct Outest(*const &'a ());
  |              -        ^^ undeclared lifetime
  |              |
  |              help: consider introducing lifetime `'a` here: `<'a>`

error[E0308]: mismatched types
 --> /tmp/icemaker_global_tempdir.TgpW6JrktGaA/rustc_testrunner_tmpdir_reporting.7eRm4vVFAtEm/mvce.rs:3:14
  |
3 | fn make() -> Outest {}
  |    ----      ^^^^^^ expected `Outest`, found `()`
  |    |
  |    implicitly returns `()` as its body has no tail or `return` expression

error: internal compiler error: compiler/rustc_pattern_analysis/src/rustc.rs:241:22: Unexpected type for `Ref` constructor: *const &'{erased} ()

thread 'rustc' panicked at compiler/rustc_pattern_analysis/src/rustc.rs:241:22:
Box<dyn Any>
stack backtrace:
   0:     0x731938db2935 - std::backtrace_rs::backtrace::libunwind::trace::h24001de405a19c29
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:     0x731938db2935 - std::backtrace_rs::backtrace::trace_unsynchronized::h52cb31f58d87e795
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x731938db2935 - std::sys::backtrace::_print_fmt::ha0a4a385e6305dc9
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/sys/backtrace.rs:68:5
   3:     0x731938db2935 - <std::sys::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hd2ac9d261fff2c5c
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/sys/backtrace.rs:44:22
   4:     0x731938e034db - core::fmt::rt::Argument::fmt::h5dd96858711c38a5
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/core/src/fmt/rt.rs:165:63
   5:     0x731938e034db - core::fmt::write::h9137aaeb0715e137
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/core/src/fmt/mod.rs:1168:21
   6:     0x731938da751f - std::io::Write::write_fmt::h3d543f59fe71748a
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/io/mod.rs:1835:15
   7:     0x731938db270e - std::sys::backtrace::_print::h4a7caef85c10fa0d
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/sys/backtrace.rs:47:5
   8:     0x731938db270e - std::sys::backtrace::print::hf1ff8c4b50b84478
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/sys/backtrace.rs:34:9
   9:     0x731938db5149 - std::panicking::default_hook::{{closure}}::h76d1d90acd3a4473
  10:     0x731938db4eec - std::panicking::default_hook::h2a49ac4243aa5140
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/panicking.rs:292:9
  11:     0x7319354acd2f - std[49f1045a74567fa7]::panicking::update_hook::<alloc[5df14249ca9505f2]::boxed::Box<rustc_driver_impl[db4e8f03b5696bb3]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x731938db5a6f - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h25f6191eb839a16b
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/alloc/src/boxed.rs:2076:9
  13:     0x731938db5a6f - std::panicking::rust_panic_with_hook::hc9c5e69e405d5d6c
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/panicking.rs:804:13
  14:     0x7319354dd7e1 - std[49f1045a74567fa7]::panicking::begin_panic::<rustc_errors[f1c452f0768a3196]::ExplicitBug>::{closure#0}
  15:     0x7319354da596 - std[49f1045a74567fa7]::sys::backtrace::__rust_end_short_backtrace::<std[49f1045a74567fa7]::panicking::begin_panic<rustc_errors[f1c452f0768a3196]::ExplicitBug>::{closure#0}, !>
  16:     0x7319354da276 - std[49f1045a74567fa7]::panicking::begin_panic::<rustc_errors[f1c452f0768a3196]::ExplicitBug>
  17:     0x7319354e6d31 - <rustc_errors[f1c452f0768a3196]::diagnostic::BugAbort as rustc_errors[f1c452f0768a3196]::diagnostic::EmissionGuarantee>::emit_producing_guarantee
  18:     0x7319359bf58c - rustc_middle[1b5811ec6d2edbd2]::util::bug::opt_span_bug_fmt::<rustc_span[b2dab8d5db9c06d4]::span_encoding::Span>::{closure#0}
  19:     0x7319359a8ada - rustc_middle[1b5811ec6d2edbd2]::ty::context::tls::with_opt::<rustc_middle[1b5811ec6d2edbd2]::util::bug::opt_span_bug_fmt<rustc_span[b2dab8d5db9c06d4]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  20:     0x7319359a895b - rustc_middle[1b5811ec6d2edbd2]::ty::context::tls::with_context_opt::<rustc_middle[1b5811ec6d2edbd2]::ty::context::tls::with_opt<rustc_middle[1b5811ec6d2edbd2]::util::bug::opt_span_bug_fmt<rustc_span[b2dab8d5db9c06d4]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  21:     0x73193346c250 - rustc_middle[1b5811ec6d2edbd2]::util::bug::bug_fmt
  22:     0x731937004d48 - rustc_pattern_analysis[9ec12d2f5d12a80]::usefulness::compute_exhaustiveness_and_usefulness::<rustc_pattern_analysis[9ec12d2f5d12a80]::rustc::RustcPatCtxt>::{closure#0}
  23:     0x731936ffee69 - rustc_pattern_analysis[9ec12d2f5d12a80]::usefulness::compute_exhaustiveness_and_usefulness::<rustc_pattern_analysis[9ec12d2f5d12a80]::rustc::RustcPatCtxt>::{closure#0}
  24:     0x731936ff92bc - rustc_pattern_analysis[9ec12d2f5d12a80]::analyze_match
  25:     0x731933de2804 - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor>::is_let_irrefutable
  26:     0x731933ddd05d - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor as rustc_middle[1b5811ec6d2edbd2]::thir::visit::Visitor>::visit_expr
  27:     0x731933ddc69d - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor as rustc_middle[1b5811ec6d2edbd2]::thir::visit::Visitor>::visit_expr
  28:     0x731933ddcbc9 - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor as rustc_middle[1b5811ec6d2edbd2]::thir::visit::Visitor>::visit_expr
  29:     0x731933ddc69d - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor as rustc_middle[1b5811ec6d2edbd2]::thir::visit::Visitor>::visit_expr
  30:     0x731933ddd504 - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor as rustc_middle[1b5811ec6d2edbd2]::thir::visit::Visitor>::visit_expr
  31:     0x731933ddc69d - <rustc_mir_build[10942160e2184657]::thir::pattern::check_match::MatchVisitor as rustc_middle[1b5811ec6d2edbd2]::thir::visit::Visitor>::visit_expr
  32:     0x731936bf41be - rustc_mir_build[10942160e2184657]::thir::pattern::check_match::check_match
  33:     0x731936bf3dd5 - rustc_query_impl[ed5fbfae2043678b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[ed5fbfae2043678b]::query_impl::check_match::dynamic_query::{closure#2}::{closure#0}, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 1usize]>>
  34:     0x731936bf347f - rustc_query_system[f4d6069fb68f5c49]::query::plumbing::try_execute_query::<rustc_query_impl[ed5fbfae2043678b]::DynamicConfig<rustc_query_system[f4d6069fb68f5c49]::query::caches::VecCache<rustc_span[b2dab8d5db9c06d4]::def_id::LocalDefId, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[ed5fbfae2043678b]::plumbing::QueryCtxt, false>
  35:     0x731936bf31dd - rustc_query_impl[ed5fbfae2043678b]::query_impl::check_match::get_query_non_incr::__rust_end_short_backtrace
  36:     0x731936c0bcc8 - rustc_mir_build[10942160e2184657]::build::mir_build
  37:     0x731936c0b38e - rustc_query_impl[ed5fbfae2043678b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[ed5fbfae2043678b]::query_impl::mir_built::dynamic_query::{closure#2}::{closure#0}, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 8usize]>>
  38:     0x731936bbe0ae - rustc_query_system[f4d6069fb68f5c49]::query::plumbing::try_execute_query::<rustc_query_impl[ed5fbfae2043678b]::DynamicConfig<rustc_query_system[f4d6069fb68f5c49]::query::caches::VecCache<rustc_span[b2dab8d5db9c06d4]::def_id::LocalDefId, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 8usize]>>, false, false, false>, rustc_query_impl[ed5fbfae2043678b]::plumbing::QueryCtxt, false>
  39:     0x731936bbdbcd - rustc_query_impl[ed5fbfae2043678b]::query_impl::mir_built::get_query_non_incr::__rust_end_short_backtrace
  40:     0x731936bff048 - rustc_mir_build[10942160e2184657]::check_unsafety::check_unsafety
  41:     0x731936bfedf1 - rustc_query_impl[ed5fbfae2043678b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[ed5fbfae2043678b]::query_impl::check_unsafety::dynamic_query::{closure#2}::{closure#0}, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 0usize]>>
  42:     0x731936bfdeea - rustc_query_system[f4d6069fb68f5c49]::query::plumbing::try_execute_query::<rustc_query_impl[ed5fbfae2043678b]::DynamicConfig<rustc_query_system[f4d6069fb68f5c49]::query::caches::VecCache<rustc_span[b2dab8d5db9c06d4]::def_id::LocalDefId, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 0usize]>>, false, false, false>, rustc_query_impl[ed5fbfae2043678b]::plumbing::QueryCtxt, false>
  43:     0x731936bfdb0b - rustc_query_impl[ed5fbfae2043678b]::query_impl::check_unsafety::get_query_non_incr::__rust_end_short_backtrace
  44:     0x731937203d2a - rustc_interface[c6ece38a3a908c28]::passes::analysis
  45:     0x731937202e07 - rustc_query_impl[ed5fbfae2043678b]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[ed5fbfae2043678b]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 1usize]>>
  46:     0x7319376360a5 - rustc_query_system[f4d6069fb68f5c49]::query::plumbing::try_execute_query::<rustc_query_impl[ed5fbfae2043678b]::DynamicConfig<rustc_query_system[f4d6069fb68f5c49]::query::caches::SingleCache<rustc_middle[1b5811ec6d2edbd2]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[ed5fbfae2043678b]::plumbing::QueryCtxt, false>
  47:     0x731937635e0f - rustc_query_impl[ed5fbfae2043678b]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  48:     0x7319374dd3d2 - rustc_interface[c6ece38a3a908c28]::interface::run_compiler::<core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>, rustc_driver_impl[db4e8f03b5696bb3]::run_compiler::{closure#0}>::{closure#1}
  49:     0x7319374b54c9 - std[49f1045a74567fa7]::sys::backtrace::__rust_begin_short_backtrace::<rustc_interface[c6ece38a3a908c28]::util::run_in_thread_with_globals<rustc_interface[c6ece38a3a908c28]::util::run_in_thread_pool_with_globals<rustc_interface[c6ece38a3a908c28]::interface::run_compiler<core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>, rustc_driver_impl[db4e8f03b5696bb3]::run_compiler::{closure#0}>::{closure#1}, core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>>::{closure#0}, core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>>
  50:     0x7319374b527a - <<std[49f1045a74567fa7]::thread::Builder>::spawn_unchecked_<rustc_interface[c6ece38a3a908c28]::util::run_in_thread_with_globals<rustc_interface[c6ece38a3a908c28]::util::run_in_thread_pool_with_globals<rustc_interface[c6ece38a3a908c28]::interface::run_compiler<core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>, rustc_driver_impl[db4e8f03b5696bb3]::run_compiler::{closure#0}>::{closure#1}, core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>>::{closure#0}, core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[3c5d2e85893f84f8]::result::Result<(), rustc_span[b2dab8d5db9c06d4]::ErrorGuaranteed>>::{closure#2} as core[3c5d2e85893f84f8]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  51:     0x731938dbf8eb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::haf6c6ed15ef7c4b2
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/alloc/src/boxed.rs:2062:9
  52:     0x731938dbf8eb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h3648257e1237816c
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/alloc/src/boxed.rs:2062:9
  53:     0x731938dbf8eb - std::sys::pal::unix::thread::Thread::new::thread_start::h379e689399d87cbf
                               at /rustc/dd104ef16315e2387fe94e8c43eb5a66e3dbd660/library/std/src/sys/pal/unix/thread.rs:108:17
  54:     0x731938b58ded - <unknown>
  55:     0x731938bdc0dc - <unknown>
  56:                0x0 - <unknown>

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 1.81.0-nightly (dd104ef16 2024-06-18) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [check_match] match-checking `main`
#1 [mir_built] building MIR for `main`
end of query stack
error: aborting due to 3 previous errors

Some errors have detailed explanations: E0261, E0308.
For more information about an error, try `rustc --explain E0261`.

[GrigorenkoPV]

searched nightlies: from nightly-2022-02-19 to nightly-2024-06-19
regressed nightly: nightly-2024-03-22
searched commit range: 1388d7a...0ad927c
regressed commit: 6a6cd65 (#122803, which is a rollup)
Same as regressed PR as in #126666

[matthiaskrgr]

probably #122749