ICE: effects: expected region for `'x/#1` (`'x/#1/1`) but found `Type(())` when instantiating args=`[false, ()]`

[matthiaskrgr]

original:

#![feature(const_trait_impl)]
#[const_trait]
trait Main {
    fn compute<T: ~const Aux>() -> u32;
}

impl const Main for () {
    fn compute<'x, 'y, 'z: 'x>() -> u32 {}
}

#[const_trait]
trait Aux {}

impl const Aux for () {}

fn main() {
    const _: u32 = <()>::compute::<()>();
}

Version information

rustc 1.80.0-nightly (12b5d3c29 2024-06-02)
binary: rustc
commit-hash: 12b5d3c29c221a4c61f9e6863f4bc1133f3e3403
commit-date: 2024-06-02
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.6

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

Program output

error[E0658]: const trait impls are experimental
 --> /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:4:19
  |
4 |     fn compute<T: ~const Aux>() -> u32;
  |                   ^^^^^^
  |
  = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
  = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
  = note: this compiler was built on 2024-06-02; consider upgrading it if it is out of date

error[E0658]: const trait impls are experimental
 --> /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:7:6
  |
7 | impl const Main for () {
  |      ^^^^^
  |
  = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
  = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
  = note: this compiler was built on 2024-06-02; consider upgrading it if it is out of date

error[E0658]: const trait impls are experimental
  --> /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:14:6
   |
14 | impl const Aux for () {}
   |      ^^^^^
   |
   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
   = note: this compiler was built on 2024-06-02; consider upgrading it if it is out of date

error[E0658]: `const_trait` is a temporary placeholder for marking a trait that is suitable for `const` `impls` and all default bodies as `const`, which may be removed or renamed in the future.
 --> /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:2:1
  |
2 | #[const_trait]
  | ^^^^^^^^^^^^^^
  |
  = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
  = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
  = note: this compiler was built on 2024-06-02; consider upgrading it if it is out of date

error[E0658]: `const_trait` is a temporary placeholder for marking a trait that is suitable for `const` `impls` and all default bodies as `const`, which may be removed or renamed in the future.
  --> /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:11:1
   |
11 | #[const_trait]
   | ^^^^^^^^^^^^^^
   |
   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
   = note: this compiler was built on 2024-06-02; consider upgrading it if it is out of date

error[E0049]: method `compute` has 0 type parameters but its trait declaration has 1 type parameter
 --> /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:8:16
  |
4 |     fn compute<T: ~const Aux>() -> u32;
  |                - expected 1 type parameter
...
8 |     fn compute<'x, 'y, 'z: 'x>() -> u32 {}
  |                ^^  ^^  ^^
  |                |
  |                found 0 type parameters

thread 'rustc' panicked at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/compiler/rustc_type_ir/src/binder.rs:780:9:
expected region for `'x/#1` ('x/#1/1) but found Type(()) when instantiating args=[false, ()]
stack backtrace:
   0:     0x769a0501dcc5 - std::backtrace_rs::backtrace::libunwind::trace::h5c601cdef598aaa0
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:     0x769a0501dcc5 - std::backtrace_rs::backtrace::trace_unsynchronized::h3304d594bcf5ce4b
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x769a0501dcc5 - std::sys_common::backtrace::_print_fmt::h2549dec49bea2d98
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/sys_common/backtrace.rs:68:5
   3:     0x769a0501dcc5 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h04c91bbe9af2a729
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x769a0506e46b - core::fmt::rt::Argument::fmt::h97420e8fd0085884
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/core/src/fmt/rt.rs:165:63
   5:     0x769a0506e46b - core::fmt::write::h01dd1670b7b9cf91
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/core/src/fmt/mod.rs:1168:21
   6:     0x769a05012a4f - std::io::Write::write_fmt::h90070e824a2a3a2f
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/io/mod.rs:1835:15
   7:     0x769a0501da9e - std::sys_common::backtrace::_print::h45ccaa1c1aca1add
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/sys_common/backtrace.rs:47:5
   8:     0x769a0501da9e - std::sys_common::backtrace::print::hf13fbbec12656116
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/sys_common/backtrace.rs:34:9
   9:     0x769a050204d9 - std::panicking::default_hook::{{closure}}::h0560bcddc75439af
  10:     0x769a0502027a - std::panicking::default_hook::hb65cbbd101f7744c
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/panicking.rs:298:9
  11:     0x769a0173fd30 - std[a775f339eb2c908d]::panicking::update_hook::<alloc[536a72e1d9fad6b4]::boxed::Box<rustc_driver_impl[7cac6a613f152b21]::install_ice_hook::{closure#0}>>::{closure#0}
  12:     0x769a05020c0b - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::hf5609484f859850d
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/alloc/src/boxed.rs:2077:9
  13:     0x769a05020c0b - std::panicking::rust_panic_with_hook::hd28b3d7b65cbce3b
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/panicking.rs:799:13
  14:     0x769a05020984 - std::panicking::begin_panic_handler::{{closure}}::ha8bcc51435d20919
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/panicking.rs:664:13
  15:     0x769a0501e189 - std::sys_common::backtrace::__rust_end_short_backtrace::hc70c274bd540ad18
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/sys_common/backtrace.rs:171:18
  16:     0x769a050206b7 - rust_begin_unwind
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/panicking.rs:652:5
  17:     0x769a0506aa03 - core::panicking::panic_fmt::hf39c48c9ef9a4449
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/core/src/panicking.rs:72:14
  18:     0x769a01be4195 - <rustc_type_ir[228918f94797f562]::binder::ArgFolder<rustc_middle[bef47f67271d9a46]::ty::context::TyCtxt>>::region_param_expected
  19:     0x769a03eae7ef - <rustc_middle[bef47f67271d9a46]::ty::generic_args::GenericArg as rustc_type_ir[228918f94797f562]::fold::TypeFoldable<rustc_middle[bef47f67271d9a46]::ty::context::TyCtxt>>::try_fold_with::<rustc_type_ir[228918f94797f562]::binder::ArgFolder<rustc_middle[bef47f67271d9a46]::ty::context::TyCtxt>>.cold
  20:     0x769a02c29e77 - <rustc_type_ir[228918f94797f562]::binder::ArgFolder<rustc_middle[bef47f67271d9a46]::ty::context::TyCtxt> as rustc_type_ir[228918f94797f562]::fold::TypeFolder<rustc_middle[bef47f67271d9a46]::ty::context::TyCtxt>>::fold_ty
  21:     0x769a032d1e7d - rustc_ty_utils[19af1cc05f4ff8a6]::abi::fn_abi_of_instance
  22:     0x769a032d1bb3 - rustc_query_impl[5794e5c3e93d6bbc]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5794e5c3e93d6bbc]::query_impl::fn_abi_of_instance::dynamic_query::{closure#2}::{closure#0}, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 16usize]>>
  23:     0x769a032cfb55 - rustc_query_system[3938cdb6d095e7a2]::query::plumbing::try_execute_query::<rustc_query_impl[5794e5c3e93d6bbc]::DynamicConfig<rustc_query_system[3938cdb6d095e7a2]::query::caches::DefaultCache<rustc_middle[bef47f67271d9a46]::ty::ParamEnvAnd<(rustc_middle[bef47f67271d9a46]::ty::instance::Instance, &rustc_middle[bef47f67271d9a46]::ty::list::RawList<(), rustc_middle[bef47f67271d9a46]::ty::Ty>)>, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 16usize]>>, false, false, false>, rustc_query_impl[5794e5c3e93d6bbc]::plumbing::QueryCtxt, false>
  24:     0x769a032cf7af - rustc_query_impl[5794e5c3e93d6bbc]::query_impl::fn_abi_of_instance::get_query_non_incr::__rust_end_short_backtrace
  25:     0x769a031c32b3 - <rustc_const_eval[6ba209fe2493db55]::interpret::eval_context::InterpCx<rustc_const_eval[6ba209fe2493db55]::const_eval::machine::CompileTimeInterpreter>>::terminator
  26:     0x769a00b4e281 - rustc_const_eval[6ba209fe2493db55]::const_eval::eval_queries::eval_to_allocation_raw_provider
  27:     0x769a0310bcb6 - rustc_query_impl[5794e5c3e93d6bbc]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5794e5c3e93d6bbc]::query_impl::eval_to_allocation_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 24usize]>>
  28:     0x769a0310b4d9 - rustc_query_system[3938cdb6d095e7a2]::query::plumbing::try_execute_query::<rustc_query_impl[5794e5c3e93d6bbc]::DynamicConfig<rustc_query_system[3938cdb6d095e7a2]::query::caches::DefaultCache<rustc_middle[bef47f67271d9a46]::ty::ParamEnvAnd<rustc_middle[bef47f67271d9a46]::mir::interpret::GlobalId>, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[5794e5c3e93d6bbc]::plumbing::QueryCtxt, false>
  29:     0x769a0310b0b0 - rustc_query_impl[5794e5c3e93d6bbc]::query_impl::eval_to_allocation_raw::get_query_non_incr::__rust_end_short_backtrace
  30:     0x769a0310c818 - rustc_const_eval[6ba209fe2493db55]::const_eval::eval_queries::eval_to_const_value_raw_provider
  31:     0x769a0310c636 - rustc_query_impl[5794e5c3e93d6bbc]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5794e5c3e93d6bbc]::query_impl::eval_to_const_value_raw::dynamic_query::{closure#2}::{closure#0}, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 24usize]>>
  32:     0x769a0310b49c - rustc_query_system[3938cdb6d095e7a2]::query::plumbing::try_execute_query::<rustc_query_impl[5794e5c3e93d6bbc]::DynamicConfig<rustc_query_system[3938cdb6d095e7a2]::query::caches::DefaultCache<rustc_middle[bef47f67271d9a46]::ty::ParamEnvAnd<rustc_middle[bef47f67271d9a46]::mir::interpret::GlobalId>, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 24usize]>>, false, false, false>, rustc_query_impl[5794e5c3e93d6bbc]::plumbing::QueryCtxt, false>
  33:     0x769a0310afb2 - rustc_query_impl[5794e5c3e93d6bbc]::query_impl::eval_to_const_value_raw::get_query_non_incr::__rust_end_short_backtrace
  34:     0x769a031e989f - <rustc_middle[bef47f67271d9a46]::hir::map::Map>::par_body_owners::<rustc_hir_analysis[8b4104a21d8e4643]::check_crate::{closure#3}>::{closure#0}
  35:     0x769a031e7cf1 - rustc_hir_analysis[8b4104a21d8e4643]::check_crate
  36:     0x769a03171cfe - rustc_interface[a03d98276cabf663]::passes::analysis
  37:     0x769a0317185b - rustc_query_impl[5794e5c3e93d6bbc]::plumbing::__rust_begin_short_backtrace::<rustc_query_impl[5794e5c3e93d6bbc]::query_impl::analysis::dynamic_query::{closure#2}::{closure#0}, rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 1usize]>>
  38:     0x769a0399b465 - rustc_query_system[3938cdb6d095e7a2]::query::plumbing::try_execute_query::<rustc_query_impl[5794e5c3e93d6bbc]::DynamicConfig<rustc_query_system[3938cdb6d095e7a2]::query::caches::SingleCache<rustc_middle[bef47f67271d9a46]::query::erase::Erased<[u8; 1usize]>>, false, false, false>, rustc_query_impl[5794e5c3e93d6bbc]::plumbing::QueryCtxt, false>
  39:     0x769a0399b1cf - rustc_query_impl[5794e5c3e93d6bbc]::query_impl::analysis::get_query_non_incr::__rust_end_short_backtrace
  40:     0x769a037eb652 - rustc_interface[a03d98276cabf663]::interface::run_compiler::<core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>, rustc_driver_impl[7cac6a613f152b21]::run_compiler::{closure#0}>::{closure#1}
  41:     0x769a037d70c9 - std[a775f339eb2c908d]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[a03d98276cabf663]::util::run_in_thread_with_globals<rustc_interface[a03d98276cabf663]::util::run_in_thread_pool_with_globals<rustc_interface[a03d98276cabf663]::interface::run_compiler<core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>, rustc_driver_impl[7cac6a613f152b21]::run_compiler::{closure#0}>::{closure#1}, core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>>::{closure#0}, core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>>
  42:     0x769a037d6e7c - <<std[a775f339eb2c908d]::thread::Builder>::spawn_unchecked_<rustc_interface[a03d98276cabf663]::util::run_in_thread_with_globals<rustc_interface[a03d98276cabf663]::util::run_in_thread_pool_with_globals<rustc_interface[a03d98276cabf663]::interface::run_compiler<core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>, rustc_driver_impl[7cac6a613f152b21]::run_compiler::{closure#0}>::{closure#1}, core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>>::{closure#0}, core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[2f142f84f3f08b4f]::result::Result<(), rustc_span[dff96a22867030c9]::ErrorGuaranteed>>::{closure#2} as core[2f142f84f3f08b4f]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  43:     0x769a0502abfb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h73c010387396631a
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/alloc/src/boxed.rs:2063:9
  44:     0x769a0502abfb - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hcaeb0c9aa85d79b5
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/alloc/src/boxed.rs:2063:9
  45:     0x769a0502abfb - std::sys::pal::unix::thread::Thread::new::thread_start::h51fdb75527a8aba4
                               at /rustc/12b5d3c29c221a4c61f9e6863f4bc1133f3e3403/library/std/src/sys/pal/unix/thread.rs:108:17
  46:     0x7699fe4aa1cf - <unknown>
  47:     0x7699fe52b6ec - <unknown>
  48:                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 (12b5d3c29 2024-06-02) running on x86_64-unknown-linux-gnu

query stack during panic:
#0 [fn_abi_of_instance] computing call ABI of `<impl at /tmp/icemaker_global_tempdir.bK55YoS20qrj/rustc_testrunner_tmpdir_reporting.MEMab5bWwSDM/mvce.rs:7:1: 7:23>::compute`
#1 [eval_to_allocation_raw] const-evaluating + checking `main::_`
end of query stack
error: aborting due to 6 previous errors

Some errors have detailed explanations: E0049, E0658.
For more information about an error, try `rustc --explain E0049`.

@rustbot label +F-effects

[cushionbadak]

By the way, it appears that the two seed files associated with this ICE issue are identical.

1: tests/crashes/121957-1.rs

rust/tests/crashes/121957-1.rs

Lines 1 to 20 in 06d99cd

	//@ known-bug: #121957
	#![feature(const_trait_impl, effects)]
	#[const_trait]
	trait Main {
	fn compute<T: ~const Aux>() -> u32;
	}
	impl const Main for () {
	fn compute<'x, 'y, 'z: 'x>() -> u32 {}
	}
	#[const_trait]
	trait Aux {}
	impl const Aux for () {}
	fn main() {
	const _: u32 = <()>::compute::<()>();
	}

2: tests/crashes/121957-2.rs

rust/tests/crashes/121957-2.rs

Lines 1 to 20 in 06d99cd

	//@ known-bug: #121957
	#![feature(const_trait_impl, effects)]
	#[const_trait]
	trait Main {
	fn compute<T: ~const Aux>() -> u32;
	}
	impl const Main for () {
	fn compute<'x, 'y, 'z: 'x>() -> u32 {}
	}
	#[const_trait]
	trait Aux {}
	impl const Aux for () {}
	fn main() {
	const _: u32 = <()>::compute::<()>();
	}

[fmease]

Fixed by new desugaring (#131985). We might want to add a regression test.