ICE: `region variables should not be hashed:`

[cushionbadak]

Code

(reduced)

struct NoDerive(i32);

impl PartialEq for NoDerive {  }

#[derive(PartialEq)]
struct WrapParam<'a, T>(&'a &'a T);

const WRAP_DOUBLY_INDIRECT_PARAM: & &WrapParam<NoDerive> = & &WrapParam(& & NoDerive(0));

fn main() {
    match WRAP_DOUBLY_INDIRECT_PARAM {
        WRAP_DOUBLY_INDIRECT_PARAM => { }
        _ => { }
    }
}

(original)

// This is part of a set of tests exploring the different ways a
// structural-match ADT might try to hold a
// non-structural-match in hidden manner that lets matches
// through that we had intended to reject.
//
// See discussion on rust-lang/rust#62307 and rust-lang/rust#62339
#![warn(indirect_structural_match)]
//@ run-pass

struct NoDerive(#[allow(dead_code)] i32);

//~| ERROR cannot find attribute `w` in this scope
impl PartialEq for NoDerive { fn eq(&self, _: &Self) -> bool { false } }

impl Eq for NoDerive { }

#[derive(PartialEq, Eq)]
struct WrapParam<'a, T>(&'a &'a T);

const WRAP_DOUBLY_INDIRECT_PARAM: & &WrapParam<NoDerive> = & &WrapParam(& & NoDerive(0));

fn main() {
    match WRAP_DOUBLY_INDIRECT_PARAM {
        WRAP_DOUBLY_INDIRECT_PARAM => { panic!("WRAP_DOUBLY_INDIRECT_PARAM matched itself"); }
        //~^ WARN must be annotated with `#[derive(PartialEq)]`
        //~| WARN this was previously accepted
        _ => { println!("WRAP_DOUBLY_INDIRECT_PARAM correctly did not match itself"); }
    }
}

Meta

rustc --version --verbose:

rustc 1.79.0-nightly (0ad927c0c 2024-03-21)
binary: rustc
commit-hash: 0ad927c0c07b65fc0dae37105e09c877c87c296a
commit-date: 2024-03-21
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.2

Error output

error[E0046]: not all trait items implemented, missing: `eq`
 --> reduced_03D683BAA43FDC5659149719B7678C979D2BBD231E786D32B542F42EE920BD91.rs:3:1
  |
3 | impl PartialEq for NoDerive {  }
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `eq` in implementation
  |
  = help: implement the missing item: `fn eq(&self, _: &NoDerive) -> bool { todo!() }`

warning: to use a constant of type `NoDerive` in a pattern, `NoDerive` must be annotated with `#[derive(PartialEq)]`
  --> reduced_03D683BAA43FDC5659149719B7678C979D2BBD231E786D32B542F42EE920BD91.rs:12:9
   |
12 |         WRAP_DOUBLY_INDIRECT_PARAM => { }
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #120362 <https://github.com/rust-lang/rust/issues/120362>
   = note: the traits must be derived, manual `impl`s are not sufficient
   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details
   = note: `#[warn(indirect_structural_match)]` on by default

Backtrace

thread 'rustc' panicked at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/compiler/rustc_type_ir/src/region_kind.rs:287:17:
region variables should not be hashed: '?11
stack backtrace:
   0:     0x7f56059cffa5 - std::backtrace_rs::backtrace::libunwind::trace::h679d01c861932e9e
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/../../backtrace/src/backtrace/libunwind.rs:105:5
   1:     0x7f56059cffa5 - std::backtrace_rs::backtrace::trace_unsynchronized::h844ab42216481d11
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f56059cffa5 - std::sys_common::backtrace::_print_fmt::hded996a88eb0ebe5
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x7f56059cffa5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h5cbf4ae00ce2987b
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f5605a20feb - core::fmt::rt::Argument::fmt::h63860774c6cb96d8
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/core/src/fmt/rt.rs:142:9
   5:     0x7f5605a20feb - core::fmt::write::h50de0697b18b6c58
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/core/src/fmt/mod.rs:1153:17
   6:     0x7f56059c4d3f - std::io::Write::write_fmt::hfc015a285764248e
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/io/mod.rs:1843:15
   7:     0x7f56059cfd7e - std::sys_common::backtrace::_print::heb3c50b6ebbd2629
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x7f56059cfd7e - std::sys_common::backtrace::print::h16dc64233af0ecc0
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x7f56059d29f9 - std::panicking::default_hook::{{closure}}::he761602674a90188
  10:     0x7f56059d2763 - std::panicking::default_hook::hf0f68f006b5fc67a
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/panicking.rs:292:9
  11:     0x7f56023ce28e - std[a6d3664d074e4e2d]::panicking::update_hook::<alloc[e5204ed3b0e852a7]::boxed::Box<rustc_driver_impl[177aae33245cb812]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x7f56059d3150 - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h910de5d7d29c18e7
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/alloc/src/boxed.rs:2029:9
  13:     0x7f56059d3150 - std::panicking::rust_panic_with_hook::h2cb61026c897c737
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/panicking.rs:783:13
  14:     0x7f56059d2ea6 - std::panicking::begin_panic_handler::{{closure}}::h35ea0cac59ee57dc
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/panicking.rs:657:13
  15:     0x7f56059d0469 - std::sys_common::backtrace::__rust_end_short_backtrace::h1d98a7fbca552aa0
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x7f56059d2bd7 - rust_begin_unwind
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/panicking.rs:645:5
  17:     0x7f5605a1d486 - core::panicking::panic_fmt::h0834a34108b44488
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/core/src/panicking.rs:72:14
  18:     0x7f5603c5b743 - <rustc_middle[3c0f42ae630e8f10]::ty::generic_args::GenericArg as rustc_data_structures[638fdda6c09fd028]::stable_hasher::HashStable<rustc_query_system[e7e333fc838440db]::ich::hcx::StableHashingContext>>::hash_stable
  19:     0x7f56039ef245 - <rustc_type_ir[615ccdf32c2e66a7]::ty_info::WithCachedTypeInfo<rustc_type_ir[615ccdf32c2e66a7]::ty_kind::TyKind<rustc_middle[3c0f42ae630e8f10]::ty::context::TyCtxt>> as rustc_data_structures[638fdda6c09fd028]::stable_hasher::HashStable<rustc_query_system[e7e333fc838440db]::ich::hcx::StableHashingContext>>::hash_stable
  20:     0x7f5603a00e4c - <rustc_type_ir[615ccdf32c2e66a7]::ty_info::WithCachedTypeInfo<rustc_middle[3c0f42ae630e8f10]::ty::consts::ConstData> as rustc_data_structures[638fdda6c09fd028]::stable_hasher::HashStable<rustc_query_system[e7e333fc838440db]::ich::hcx::StableHashingContext>>::hash_stable
  21:     0x7f5602c0bb9b - rustc_query_impl[3d32d7d6f9825ea7]::plumbing::query_key_hash_verify::<rustc_query_impl[3d32d7d6f9825ea7]::DynamicConfig<rustc_query_system[e7e333fc838440db]::query::caches::DefaultCache<rustc_middle[3c0f42ae630e8f10]::ty::consts::Const, rustc_middle[3c0f42ae630e8f10]::query::erase::Erased<[u8; 24usize]>>, false, false, false>>::{closure#0}
  22:     0x7f5604717733 - <rustc_query_system[e7e333fc838440db]::query::caches::DefaultCache<rustc_middle[3c0f42ae630e8f10]::ty::consts::Const, rustc_middle[3c0f42ae630e8f10]::query::erase::Erased<[u8; 24usize]>> as rustc_query_system[e7e333fc838440db]::query::caches::QueryCache>::iter
  23:     0x7f560471759f - rustc_query_impl[3d32d7d6f9825ea7]::query_impl::destructure_const::query_key_hash_verify
  24:     0x7f560448c385 - rustc_interface[773e0c8b9ac0b15a]::interface::run_compiler::<core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>, rustc_driver_impl[177aae33245cb812]::run_compiler::{closure#0}>::{closure#0}
  25:     0x7f5604555987 - std[a6d3664d074e4e2d]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[773e0c8b9ac0b15a]::util::run_in_thread_with_globals<rustc_interface[773e0c8b9ac0b15a]::util::run_in_thread_pool_with_globals<rustc_interface[773e0c8b9ac0b15a]::interface::run_compiler<core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>, rustc_driver_impl[177aae33245cb812]::run_compiler::{closure#0}>::{closure#0}, core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>>::{closure#0}, core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>>
  26:     0x7f56045557b4 - <<std[a6d3664d074e4e2d]::thread::Builder>::spawn_unchecked_<rustc_interface[773e0c8b9ac0b15a]::util::run_in_thread_with_globals<rustc_interface[773e0c8b9ac0b15a]::util::run_in_thread_pool_with_globals<rustc_interface[773e0c8b9ac0b15a]::interface::run_compiler<core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>, rustc_driver_impl[177aae33245cb812]::run_compiler::{closure#0}>::{closure#0}, core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>>::{closure#0}, core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[f542d2235e74f536]::result::Result<(), rustc_span[3935dbab7cef6955]::ErrorGuaranteed>>::{closure#1} as core[f542d2235e74f536]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  27:     0x7f56059dc919 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h1c605e92c63edbd9
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/alloc/src/boxed.rs:2015:9
  28:     0x7f56059dc919 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h17dff47eba1ee89b
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/alloc/src/boxed.rs:2015:9
  29:     0x7f56059dc919 - std::sys::pal::unix::thread::Thread::new::thread_start::h9a9d47ad2c64592d
                               at /rustc/0ad927c0c07b65fc0dae37105e09c877c87c296a/library/std/src/sys/pal/unix/thread.rs:108:17
  30:     0x7f55ff26bac3 - <unknown>
  31:     0x7f55ff2fd850 - <unknown>
  32:                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 attach the file at `/home/jb/workspace/placeholder/rustc-ice-2024-03-22T08_27_43-31361.txt` to your bug report

note: compiler flags: -Z incremental-verify-ich=yes -Z dump-mir=all

query stack during panic:
end of query stack
error: aborting due to 1 previous error; 1 warning emitted

For more information about this error, try `rustc --explain E0046`.

[matthiaskrgr]

duplicate of #112397