ICE: cannot relate bound region

[Daniel-Anker-Hermansen]

Code

fn main() {
    foo(bar);
}

fn bar(r: [&usize]) { }

fn foo(f: impl Fn(&[&usize])) { }

Meta

rustc --version --verbose:

rustc 1.68.0 (2c8cc3432 2023-03-06)
binary: rustc
commit-hash: 2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74
commit-date: 2023-03-06
host: x86_64-unknown-linux-gnu
release: 1.68.0
LLVM version: 15.0.6

Error output

error: internal compiler error: compiler/rustc_infer/src/infer/region_constraints/mod.rs:568:17: cannot relate bound region: ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrNamed(DefId(0:6 ~ intenal_panic[553d]::bar::'_), '_) }) <= ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrNamed(DefId(0:9 ~ intenal_panic[553d]::foo::'_#1), '_) })

Backtrace

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/compiler/rustc_errors/src/lib.rs:987:33
stack backtrace:
   0:     0x7f274b29659a - std::backtrace_rs::backtrace::libunwind::trace::h595f06c70adcc478
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7f274b29659a - std::backtrace_rs::backtrace::trace_unsynchronized::h177a0149c76cdde9
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7f274b29659a - std::sys_common::backtrace::_print_fmt::hc0701fd2c3530c58
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/sys_common/backtrace.rs:65:5
   3:     0x7f274b29659a - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hd4cd115d8750fd6c
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/sys_common/backtrace.rs:44:22
   4:     0x7f274b2f839e - core::fmt::write::h93e2f5923c7eca08
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/fmt/mod.rs:1213:17
   5:     0x7f274b286be5 - std::io::Write::write_fmt::h8162dbb45f0b9e62
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/io/mod.rs:1682:15
   6:     0x7f274b296365 - std::sys_common::backtrace::_print::h1835ef8a8f9066da
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/sys_common/backtrace.rs:47:5
   7:     0x7f274b296365 - std::sys_common::backtrace::print::hcb5e6388b9235f41
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/sys_common/backtrace.rs:34:9
   8:     0x7f274b29912f - std::panicking::default_hook::{{closure}}::h9c084969ccf9a722
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/panicking.rs:267:22
   9:     0x7f274b298e6b - std::panicking::default_hook::h68fa2ba3c3c6c12f
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/panicking.rs:286:9
  10:     0x7f274e5e56e4 - <rustc_driver[f4ad927b3c57833d]::DEFAULT_HOOK::{closure#0}::{closure#0} as core[d16e85342ea223d9]::ops::function::FnOnce<(&core[d16e85342ea223d9]::panic::panic_info::PanicInfo,)>>::call_once::{shim:vtable#0}
  11:     0x7f274b29996a - <alloc::boxed::Box<F,A> as core::ops::function::Fn<Args>>::call::h4e6ced11e07d8b24
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/alloc/src/boxed.rs:2002:9
  12:     0x7f274b29996a - std::panicking::rust_panic_with_hook::h8d5c434518ef298c
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/panicking.rs:692:13
  13:     0x7f274e8a1501 - std[3da461b304582a2c]::panicking::begin_panic::<rustc_errors[41d09747e2f98dea]::ExplicitBug>::{closure#0}
  14:     0x7f274e899e56 - std[3da461b304582a2c]::sys_common::backtrace::__rust_end_short_backtrace::<std[3da461b304582a2c]::panicking::begin_panic<rustc_errors[41d09747e2f98dea]::ExplicitBug>::{closure#0}, !>
  15:     0x7f274e929df6 - std[3da461b304582a2c]::panicking::begin_panic::<rustc_errors[41d09747e2f98dea]::ExplicitBug>
  16:     0x7f274e929de6 - std[3da461b304582a2c]::panic::panic_any::<rustc_errors[41d09747e2f98dea]::ExplicitBug>
  17:     0x7f274e928b92 - <rustc_errors[41d09747e2f98dea]::HandlerInner>::span_bug::<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span, &alloc[5b05b59796bdfb5c]::string::String>
  18:     0x7f274e928a37 - <rustc_errors[41d09747e2f98dea]::Handler>::span_bug::<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span, &alloc[5b05b59796bdfb5c]::string::String>
  19:     0x7f274e8ddf9b - rustc_middle[eb7209f5870e9fb7]::util::bug::opt_span_bug_fmt::<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span>::{closure#0}
  20:     0x7f274e8ddfea - rustc_middle[eb7209f5870e9fb7]::ty::context::tls::with_opt::<rustc_middle[eb7209f5870e9fb7]::util::bug::opt_span_bug_fmt<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span>::{closure#0}, !>::{closure#0}
  21:     0x7f274e8dd0aa - rustc_middle[eb7209f5870e9fb7]::ty::context::tls::with_context_opt::<rustc_middle[eb7209f5870e9fb7]::ty::context::tls::with_opt<rustc_middle[eb7209f5870e9fb7]::util::bug::opt_span_bug_fmt<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span>::{closure#0}, !>::{closure#0}, !>
  22:     0x7f274e8dcfd6 - rustc_middle[eb7209f5870e9fb7]::util::bug::opt_span_bug_fmt::<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span>
  23:     0x7f274e8dcf94 - rustc_middle[eb7209f5870e9fb7]::util::bug::span_bug_fmt::<rustc_span[4bb3e3ecb57f95d5]::span_encoding::Span>
  24:     0x7f274c573fa4 - <rustc_middle[eb7209f5870e9fb7]::ty::sty::Region as rustc_middle[eb7209f5870e9fb7]::ty::relate::Relate>::relate::<rustc_infer[41785f830319e09c]::infer::equate::Equate>
  25:     0x7f274c56e926 - rustc_middle[eb7209f5870e9fb7]::ty::relate::super_relate_tys::<rustc_infer[41785f830319e09c]::infer::equate::Equate>
  26:     0x7f274c56c25e - <rustc_infer[41785f830319e09c]::infer::equate::Equate as rustc_middle[eb7209f5870e9fb7]::ty::relate::TypeRelation>::tys
  27:     0x7f274c56f1ec - rustc_middle[eb7209f5870e9fb7]::ty::relate::super_relate_tys::<rustc_infer[41785f830319e09c]::infer::equate::Equate>
  28:     0x7f274c56c25e - <rustc_infer[41785f830319e09c]::infer::equate::Equate as rustc_middle[eb7209f5870e9fb7]::ty::relate::TypeRelation>::tys
  29:     0x7f274cea5d23 - <rustc_infer[41785f830319e09c]::infer::InferCtxt>::commit_if_ok::<rustc_infer[41785f830319e09c]::infer::InferOk<()>, rustc_middle[eb7209f5870e9fb7]::ty::error::TypeError, <rustc_infer[41785f830319e09c]::infer::at::Trace>::eq<rustc_middle[eb7209f5870e9fb7]::ty::Ty>::{closure#0}>
  30:     0x7f274cea5c16 - <rustc_infer[41785f830319e09c]::infer::at::At>::eq::<rustc_middle[eb7209f5870e9fb7]::ty::Ty>
  31:     0x7f274f1c3bfe - <rustc_infer[41785f830319e09c]::infer::InferCtxt>::can_eq::<rustc_middle[eb7209f5870e9fb7]::ty::Ty>
  32:     0x7f274f1a6b42 - rustc_trait_selection[94d7ef6b5a6b8462]::traits::error_reporting::suggestions::hint_missing_borrow
  33:     0x7f274f249fe4 - <rustc_infer[41785f830319e09c]::infer::error_reporting::TypeErrCtxt as rustc_trait_selection[94d7ef6b5a6b8462]::traits::error_reporting::suggestions::TypeErrCtxtExt>::report_closure_arg_mismatch
  34:     0x7f274f259e38 - <rustc_infer[41785f830319e09c]::infer::error_reporting::TypeErrCtxt as rustc_trait_selection[94d7ef6b5a6b8462]::traits::error_reporting::TypeErrCtxtExt>::report_selection_error
  35:     0x7f274f263817 - <rustc_infer[41785f830319e09c]::infer::error_reporting::TypeErrCtxt as rustc_trait_selection[94d7ef6b5a6b8462]::traits::error_reporting::InferCtxtPrivExt>::report_fulfillment_error
  36:     0x7f274f256e7f - <rustc_infer[41785f830319e09c]::infer::error_reporting::TypeErrCtxt as rustc_trait_selection[94d7ef6b5a6b8462]::traits::error_reporting::TypeErrCtxtExt>::report_fulfillment_errors
  37:     0x7f274c7ebd65 - <rustc_hir_typeck[7533f7cabd9af3c4]::fn_ctxt::FnCtxt>::check_argument_types
  38:     0x7f274d8f30ce - <rustc_hir_typeck[7533f7cabd9af3c4]::fn_ctxt::FnCtxt>::check_call
  39:     0x7f274c7710c2 - <rustc_hir_typeck[7533f7cabd9af3c4]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  40:     0x7f274c7a6e73 - <rustc_hir_typeck[7533f7cabd9af3c4]::fn_ctxt::FnCtxt>::check_block_with_expected
  41:     0x7f274c77154c - <rustc_hir_typeck[7533f7cabd9af3c4]::fn_ctxt::FnCtxt>::check_expr_with_expectation_and_args
  42:     0x7f274c70c071 - <rustc_hir_typeck[7533f7cabd9af3c4]::fn_ctxt::FnCtxt>::check_return_expr
  43:     0x7f274c702fa2 - rustc_hir_typeck[7533f7cabd9af3c4]::check::check_fn
  44:     0x7f274c6eb85e - rustc_hir_typeck[7533f7cabd9af3c4]::typeck
  45:     0x7f274c659bf7 - <rustc_query_system[e5b40bf290de15d8]::dep_graph::graph::DepGraph<rustc_middle[eb7209f5870e9fb7]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[eb7209f5870e9fb7]::ty::context::TyCtxt, rustc_span[4bb3e3ecb57f95d5]::def_id::LocalDefId, &rustc_middle[eb7209f5870e9fb7]::ty::typeck_results::TypeckResults>
  46:     0x7f274c65174b - rustc_query_system[e5b40bf290de15d8]::query::plumbing::try_execute_query::<rustc_query_impl[3a6baddf07124ab7]::queries::typeck, rustc_query_impl[3a6baddf07124ab7]::plumbing::QueryCtxt>
  47:     0x7f274dd38aad - rustc_data_structures[f387d52c0b9780fc]::sync::par_for_each_in::<&[rustc_span[4bb3e3ecb57f95d5]::def_id::LocalDefId], <rustc_middle[eb7209f5870e9fb7]::hir::map::Map>::par_body_owners<rustc_hir_typeck[7533f7cabd9af3c4]::typeck_item_bodies::{closure#0}>::{closure#0}>
  48:     0x7f274dd38853 - rustc_hir_typeck[7533f7cabd9af3c4]::typeck_item_bodies
  49:     0x7f274dd4fa07 - <rustc_query_system[e5b40bf290de15d8]::dep_graph::graph::DepGraph<rustc_middle[eb7209f5870e9fb7]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[eb7209f5870e9fb7]::ty::context::TyCtxt, (), ()>
  50:     0x7f274db628e6 - rustc_query_system[e5b40bf290de15d8]::query::plumbing::try_execute_query::<rustc_query_impl[3a6baddf07124ab7]::queries::typeck_item_bodies, rustc_query_impl[3a6baddf07124ab7]::plumbing::QueryCtxt>
  51:     0x7f274df9eefb - <rustc_query_impl[3a6baddf07124ab7]::Queries as rustc_middle[eb7209f5870e9fb7]::ty::query::QueryEngine>::typeck_item_bodies
  52:     0x7f274ca90892 - <rustc_session[b580c712976fc965]::session::Session>::time::<(), rustc_hir_analysis[9174c993ab369dfd]::check_crate::{closure#7}>
  53:     0x7f274ca8fd12 - rustc_hir_analysis[9174c993ab369dfd]::check_crate
  54:     0x7f274ca8f96b - rustc_interface[3781616314f5d936]::passes::analysis
  55:     0x7f274dd07b16 - <rustc_query_system[e5b40bf290de15d8]::dep_graph::graph::DepGraph<rustc_middle[eb7209f5870e9fb7]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[eb7209f5870e9fb7]::ty::context::TyCtxt, (), core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>
  56:     0x7f274dd06cd1 - rustc_query_system[e5b40bf290de15d8]::query::plumbing::try_execute_query::<rustc_query_impl[3a6baddf07124ab7]::queries::analysis, rustc_query_impl[3a6baddf07124ab7]::plumbing::QueryCtxt>
  57:     0x7f274df9b7aa - <rustc_query_impl[3a6baddf07124ab7]::Queries as rustc_middle[eb7209f5870e9fb7]::ty::query::QueryEngine>::analysis
  58:     0x7f274d7c5850 - <rustc_interface[3781616314f5d936]::passes::QueryContext>::enter::<rustc_driver[f4ad927b3c57833d]::run_compiler::{closure#1}::{closure#2}::{closure#2}, core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>
  59:     0x7f274d7c32c4 - rustc_span[4bb3e3ecb57f95d5]::with_source_map::<core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>, rustc_interface[3781616314f5d936]::interface::run_compiler<core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>, rustc_driver[f4ad927b3c57833d]::run_compiler::{closure#1}>::{closure#0}::{closure#0}>
  60:     0x7f274d7bbce4 - <scoped_tls[1a6b834cb64348ef]::ScopedKey<rustc_span[4bb3e3ecb57f95d5]::SessionGlobals>>::set::<rustc_interface[3781616314f5d936]::interface::run_compiler<core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>, rustc_driver[f4ad927b3c57833d]::run_compiler::{closure#1}>::{closure#0}, core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>
  61:     0x7f274d7bb3e2 - std[3da461b304582a2c]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[3781616314f5d936]::util::run_in_thread_pool_with_globals<rustc_interface[3781616314f5d936]::interface::run_compiler<core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>, rustc_driver[f4ad927b3c57833d]::run_compiler::{closure#1}>::{closure#0}, core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>
  62:     0x7f274d7bb18a - <<std[3da461b304582a2c]::thread::Builder>::spawn_unchecked_<rustc_interface[3781616314f5d936]::util::run_in_thread_pool_with_globals<rustc_interface[3781616314f5d936]::interface::run_compiler<core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>, rustc_driver[f4ad927b3c57833d]::run_compiler::{closure#1}>::{closure#0}, core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[d16e85342ea223d9]::result::Result<(), rustc_errors[41d09747e2f98dea]::ErrorGuaranteed>>::{closure#1} as core[d16e85342ea223d9]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  63:     0x7f274b2a3823 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h1c0f3664d7ced314
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/alloc/src/boxed.rs:1988:9
  64:     0x7f274b2a3823 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::h67647c21c6c4968a
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/alloc/src/boxed.rs:1988:9
  65:     0x7f274b2a3823 - std::sys::unix::thread::Thread::new::thread_start::h355d348ba593a22c
                               at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/sys/unix/thread.rs:108:17
  66:     0x7f274afdab43 - start_thread
                               at ./nptl/./nptl/pthread_create.c:442:8
  67:     0x7f274b06ca00 - clone3
                               at ./misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
  68:                0x0 - <unknown>

note: 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: rustc 1.68.0 (2c8cc3432 2023-03-06) running on x86_64-unknown-linux-gnu

note: compiler flags: --crate-type bin -C embed-bitcode=no -C debuginfo=2 -C incremental=[REDACTED]

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
#0 [typeck] type-checking `main`
#1 [typeck_item_bodies] type-checking all item bodies
#2 [analysis] running analysis passes on this crate
end of query stack

[langston-barrett]

I can reproduce this on 1.68 but not on nightly.

rustc 1.70.0-nightly (13afbdaa0 2023-03-17)
binary: rustc
commit-hash: 13afbdaa0655dda23d7129e59ac48f1ec88b2084
commit-date: 2023-03-17
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7

[jyn514]

Might be a duplicate of #109420.

[aliemjay]

The ICE was introduced in #106891 (1.68-stable) and fixed by #107306 (1.69-beta).

This is strictly an error to ICE regression that seems to have a significant impact given the amount of issues reported so far.

@rustbot label regression-from-stable-to-stable