[ICE]: Region parameter out of range when substituting in region 'a (index=2, substs = ['_#1r, '_#1r])

[dlon]

Code

//
// crate1/src/lib.rs
//

pub trait T {}
impl T for () {}

pub struct S {}

impl S {
    pub async fn f<'a>(&self) -> impl T + 'a {
        ()
    }
}

//
// crate2/src/lib.rs
//

use crate1::S;

async fn f() {
    S{}.f().await;
}

Affected release channels

• Previous Stable
• Current Stable
• Current Beta
• Current Nightly

Rust Version

rustc 1.68.0-nightly (3984bc583 2023-01-17)
binary: rustc
commit-hash: 3984bc5833db8bfb0acc522c9775383e4171f3de
commit-date: 2023-01-17
host: x86_64-pc-windows-msvc
release: 1.68.0-nightly
LLVM version: 15.0.6

Current error output

No response

Backtrace

error: internal compiler error: compiler\rustc_middle\src\ty\subst.rs:794:13: Region parameter out of range when substituting in region 'a (index=2, substs = ['_#1r, '_#1r])

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/3984bc5833db8bfb0acc522c9775383e4171f3de\compiler\rustc_errors\src\lib.rs:1609:9
stack backtrace:
   0:     0x7ffdc5e99cc2 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h60a70252d856bd46
   1:     0x7ffdc5ed637b - core::fmt::write::h49075516e1cb5709
   2:     0x7ffdc5e8cc8a - <std::io::IoSlice as core::fmt::Debug>::fmt::h19762f7eafdc2925
   3:     0x7ffdc5e99a0b - std::sys::common::alloc::realloc_fallback::h0dd47069a25a560c
   4:     0x7ffdc5e9d3b9 - std::panicking::default_hook::h49984910299ea3cd
   5:     0x7ffdc5e9d03b - std::panicking::default_hook::h49984910299ea3cd
   6:     0x7ffdac78e37f - rustc_driver[7a77046e146b4f29]::describe_lints
   7:     0x7ffdc5e9dd1f - std::panicking::rust_panic_with_hook::h475d8178a36dbde4
   8:     0x7ffdacc8d1a3 - <rustc_middle[852c0ea678a80eaa]::ty::instance::InstanceDef as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
   9:     0x7ffdacc8d129 - <rustc_middle[852c0ea678a80eaa]::ty::instance::InstanceDef as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
  10:     0x7ffdacd0d4c9 - <rustc_middle[852c0ea678a80eaa]::ty::print::pretty::TraitRefPrintOnlyTraitPath as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
  11:     0x7ffdaccc5259 - <rustc_middle[852c0ea678a80eaa]::ty::subst::UserSubsts as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
  12:     0x7ffdaccc3a00 - <rustc_middle[852c0ea678a80eaa]::ty::subst::UserSubsts as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
  13:     0x7ffdaccc3212 - <rustc_middle[852c0ea678a80eaa]::ty::subst::UserSubsts as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
  14:     0x7ffdaccee33a - rustc_middle[852c0ea678a80eaa]::util::bug::bug_fmt
  15:     0x7ffdaccedcbd - <rustc_middle[852c0ea678a80eaa]::ty::consts::kind::UnevaluatedConst as rustc_errors[713f76e651ed9de9]::diagnostic::IntoDiagnosticArg>::into_diagnostic_arg
  16:     0x7ffdaccedc81 - <rustc_middle[852c0ea678a80eaa]::ty::consts::kind::UnevaluatedConst as rustc_errors[713f76e651ed9de9]::diagnostic::IntoDiagnosticArg>::into_diagnostic_arg
  17:     0x7ffdaccee278 - rustc_middle[852c0ea678a80eaa]::util::bug::bug_fmt
  18:     0x7ffdaccee1f5 - rustc_middle[852c0ea678a80eaa]::util::bug::bug_fmt
  19:     0x7ffdaccb6f23 - <rustc_middle[852c0ea678a80eaa]::ty::subst::GenericArg as rustc_middle[852c0ea678a80eaa]::ty::context::Lift>::lift_to_tcx
  20:     0x7ffdaaf3e025 - <rustc_middle[852c0ea678a80eaa]::ty::generics::GenericPredicates>::instantiate_identity
  21:     0x7ffdab6e0f16 - rustc_trait_selection[88b1e147c41b03db]::traits::wf::predicate_obligations
  22:     0x7ffdab6de8f2 - rustc_trait_selection[88b1e147c41b03db]::traits::wf::predicate_obligations
  23:     0x7ffdab70f912 - <rustc_trait_selection[88b1e147c41b03db]::traits::fulfill::FulfillProcessor as rustc_data_structures[a3cb96cea1ba54ce]::obligation_forest::ObligationProcessor>::process_obligation
  24:     0x7ffdab769e94 - <rustc_infer[b8df4eaaa31c36d3]::infer::InferCtxt as rustc_trait_selection[88b1e147c41b03db]::traits::outlives_bounds::InferCtxtExt>::implied_outlives_bounds
  25:     0x7ffdab70c8cf - <rustc_trait_selection[88b1e147c41b03db]::traits::fulfill::FulfillmentContext as rustc_infer[b8df4eaaa31c36d3]::traits::engine::TraitEngine>::select_where_possible
  26:     0x7ffdaac27bfe - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::try_coerce
  27:     0x7ffdaaca5e7a - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::resolve_type_vars_in_body
  28:     0x7ffdaac32573 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  29:     0x7ffdaac9154d - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::check_struct_path
  30:     0x7ffdaac34b47 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  31:     0x7ffdaaca5a38 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::resolve_type_vars_in_body
  32:     0x7ffdaac32573 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  33:     0x7ffdaac8fcff - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::check_struct_path
  34:     0x7ffdaac30aa9 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  35:     0x7ffdaac32b08 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  36:     0x7ffdaac8fe6d - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::check_struct_path
  37:     0x7ffdaac30aa9 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  38:     0x7ffdaac55891 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  39:     0x7ffdaad0bbc5 - <rustc_hir_typeck[da3e56a72a260ac8]::inherited::Inherited>::build
  40:     0x7ffda9a1649b - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::check_expr_closure
  41:     0x7ffdaac3430d - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  42:     0x7ffdaac7cc4e - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::probe_instantiate_query_response
  43:     0x7ffdaabf3e01 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::check_call
  44:     0x7ffdaac30652 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  45:     0x7ffdaac55891 - <rustc_hir_typeck[da3e56a72a260ac8]::fn_ctxt::FnCtxt>::demand_coerce
  46:     0x7ffdaad0bbc5 - <rustc_hir_typeck[da3e56a72a260ac8]::inherited::Inherited>::build
  47:     0x7ffdaacfff77 - <rustc_hir_typeck[da3e56a72a260ac8]::inherited::Inherited>::build
  48:     0x7ffdaad217a0 - <rustc_hir_typeck[da3e56a72a260ac8]::gather_locals::GatherLocalsVisitor as rustc_hir[108e8bcf66bd93db]::intravisit::Visitor>::visit_pat
  49:     0x7ffda9eca1a5 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_raw_bytes
  50:     0x7ffdab478299 - <rustc_middle[852c0ea678a80eaa]::ty::Visibility as rustc_privacy[1256a66fe85f6ffd]::VisibilityLike>::new_min
  51:     0x7ffdab5488b3 - <rustc_query_impl[ee87962b7b8b59b]::Queries as rustc_middle[852c0ea678a80eaa]::ty::query::QueryEngine>::as_any
  52:     0x7ffdab0a84dd - <rustc_mir_build[167d3f106e23a8ce]::thir::pattern::usefulness::PatStack>::head
  53:     0x7ffda9ec06c8 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_raw_bytes
  54:     0x7ffdab482c59 - <rustc_middle[852c0ea678a80eaa]::ty::Visibility as rustc_privacy[1256a66fe85f6ffd]::VisibilityLike>::new_min
  55:     0x7ffdab02b49c - <rustc_middle[852c0ea678a80eaa]::lint::ShallowLintLevelMap>::lint_level_id_at_node
  56:     0x7ffda9ec0e09 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_raw_bytes
  57:     0x7ffdab47e609 - <rustc_middle[852c0ea678a80eaa]::ty::Visibility as rustc_privacy[1256a66fe85f6ffd]::VisibilityLike>::new_min
  58:     0x7ffdab1e5895 - <rustc_mir_transform[b24cd75b40599810]::check_unsafety::UnsafetyChecker as rustc_middle[852c0ea678a80eaa]::mir::visit::Visitor>::visit_place
  59:     0x7ffdab1d9118 - <rustc_mir_transform[b24cd75b40599810]::shim::DropShimElaborator as rustc_mir_dataflow[c5db10d3eb5ed1b6]::elaborate_drops::DropElaborator>::drop_style
  60:     0x7ffda9eca1a5 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_raw_bytes
  61:     0x7ffdab449f4f - <rustc_middle[852c0ea678a80eaa]::ty::Visibility as rustc_privacy[1256a66fe85f6ffd]::VisibilityLike>::new_min
  62:     0x7ffda9cf1a8b - rustc_privacy[1256a66fe85f6ffd]::provide
  63:     0x7ffda9f05441 - <&[rustc_span[9a32fcdfb560e918]::def_id::DefId] as rustc_serialize[fb2cd6d42a10ac66]::serialize::Decodable<rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheDecoder>>::decode
  64:     0x7ffdab57fe54 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_u32
  65:     0x7ffdab57fdf4 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_u32
  66:     0x7ffdab57fdf4 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_u32
  67:     0x7ffdab57fdf4 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_u32
  68:     0x7ffdab57fdf4 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_u32
  69:     0x7ffda9cf4a56 - rustc_privacy[1256a66fe85f6ffd]::provide
  70:     0x7ffda9e8c051 - <rustc_query_impl[ee87962b7b8b59b]::Queries as rustc_middle[852c0ea678a80eaa]::ty::query::QueryEngine>::try_mark_green
  71:     0x7ffda99b6e20 - rustc_hir_analysis[5f44298b84aa60ac]::hir_wf_check::provide
  72:     0x7ffda99964b0 - rustc_hir_analysis[5f44298b84aa60ac]::check_crate
  73:     0x7ffda9ac573d - rustc_interface[296d29f5832b901f]::passes::analysis
  74:     0x7ffda9eeb6e9 - <rustc_query_impl[ee87962b7b8b59b]::on_disk_cache::CacheEncoder as rustc_serialize[fb2cd6d42a10ac66]::serialize::Encoder>::emit_raw_bytes
  75:     0x7ffda9e0c5c6 - rustc_privacy[1256a66fe85f6ffd]::provide
  76:     0x7ffda9e89a5f - <rustc_query_impl[ee87962b7b8b59b]::Queries as rustc_middle[852c0ea678a80eaa]::ty::query::QueryEngine>::try_mark_green
  77:     0x7ffda98ad2e5 - <core[4e164737ea2805f4]::ops::range::Range<usize> as core[4e164737ea2805f4]::convert::From<regex[96286c4a5f387064]::re_unicode::Match>>::from
  78:     0x7ffda98bee58 - rustc_driver[7a77046e146b4f29]::args::arg_expand_all
  79:     0x7ffda98a31e2 - <core[4e164737ea2805f4]::ops::range::Range<usize> as core[4e164737ea2805f4]::convert::From<regex[96286c4a5f387064]::re_unicode::Match>>::from
  80:     0x7ffda98be303 - rustc_driver[7a77046e146b4f29]::args::arg_expand_all
  81:     0x7ffda98ae463 - <core[4e164737ea2805f4]::ops::range::Range<usize> as core[4e164737ea2805f4]::convert::From<regex[96286c4a5f387064]::re_unicode::Match>>::from
  82:     0x7ffda98a6fdd - <core[4e164737ea2805f4]::ops::range::Range<usize> as core[4e164737ea2805f4]::convert::From<regex[96286c4a5f387064]::re_unicode::Match>>::from
  83:     0x7ffdc5eb087c - std::sys::windows::thread::Thread::new::h0e77efb359f7341a
  84:     0x7ffe45ec26bd - BaseThreadInitThunk
  85:     0x7ffe479adfb8 - RtlUserThreadStart

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-nightly (3984bc583 2023-01-17) running on x86_64-pc-windows-msvc

note: compiler flags: --crate-type lib -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 `f`
#1 [thir_body] building THIR for `f`
#2 [mir_built] building MIR for `f`
#3 [unsafety_check_result] unsafety-checking `f`
#4 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `crate2`

Anything else?

I cannot get this to fail unless S is imported from another crate.

This might be a duplicate of #105519.

[compiler-errors]

I think this regressed in #106759 😓

[compiler-errors]

searched nightlies: from nightly-2023-01-01 to nightly-2023-01-18
regressed nightly: nightly-2023-01-14
searched commit range: 61a415b...0b90256
regressed commit: 86ad69d

bisected with cargo-bisect-rustc v0.6.5

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start=2023-01-01