ICE: `StableHasher`: unexpected region `'_#0r`

[boulanlo]

I recently updated my nightly toolchain and our project (still not open-sourced) ICE'd. I managed to reduce the problem to a minimal working example:

Code

#![feature(ptr_metadata)]

trait Bar: Sized + 'static { }

struct Foo<B: Bar> {
    marker: std::marker::PhantomData<B>,
}

impl<B: Bar> Foo<B> {
    fn foo<T: ?Sized>(value: &T) {
        std::ptr::metadata(value);
    }
}

Meta

rustc --version --verbose:

rustc 1.61.0-nightly (63b8f01bb 2022-03-24)
binary: rustc
commit-hash: 63b8f01bb5ca277e7df8d7efe094ed4244c1790c
commit-date: 2022-03-24
host: x86_64-unknown-linux-gnu
release: 1.61.0-nightly
LLVM version: 14.0.0

Error output

error: internal compiler error: compiler/rustc_middle/src/ty/impls_ty.rs:128:17: StableHasher: unexpected region '_#0r

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1261:9

Backtrace

error: internal compiler error: compiler/rustc_middle/src/ty/impls_ty.rs:128:17: StableHasher: unexpected region '_#0r

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1261:9
stack backtrace:
   0:     0x7fa26fa9d55d - std::backtrace_rs::backtrace::libunwind::trace::h2d2403a4858e54e0
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:     0x7fa26fa9d55d - std::backtrace_rs::backtrace::trace_unsynchronized::h19488f91fb99335d
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:     0x7fa26fa9d55d - std::sys_common::backtrace::_print_fmt::hc7dc3caa1b1fa1a8
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/sys_common/backtrace.rs:66:5
   3:     0x7fa26fa9d55d - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hdd9bf0d62a609be4
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/sys_common/backtrace.rs:45:22
   4:     0x7fa26faf755c - core::fmt::write::h5aa356cee5fb9fa9
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/core/src/fmt/mod.rs:1190:17
   5:     0x7fa26fa8eb51 - std::io::Write::write_fmt::h5f1c72988edc233a
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/io/mod.rs:1655:15
   6:     0x7fa26faa0645 - std::sys_common::backtrace::_print::hf7422c13ad711003
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/sys_common/backtrace.rs:48:5
   7:     0x7fa26faa0645 - std::sys_common::backtrace::print::hd1d7cd277e511da8
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/sys_common/backtrace.rs:35:9
   8:     0x7fa26faa0645 - std::panicking::default_hook::{{closure}}::h197cc907105123d7
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/panicking.rs:295:22
   9:     0x7fa26faa02f9 - std::panicking::default_hook::h1359dace8bca1122
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/panicking.rs:314:9
  10:     0x7fa2702ce2e1 - rustc_driver[dfa02f50b2a2e61e]::DEFAULT_HOOK::{closure#0}::{closure#0}
  11:     0x7fa26faa0d90 - std::panicking::rust_panic_with_hook::h6964c34f5177236d
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/panicking.rs:702:17
  12:     0x7fa2713751f1 - std[93bbb3cd3e7c1062]::panicking::begin_panic::<rustc_errors[b882cf8cc0f2d9b3]::ExplicitBug>::{closure#0}
  13:     0x7fa2713750b6 - std[93bbb3cd3e7c1062]::sys_common::backtrace::__rust_end_short_backtrace::<std[93bbb3cd3e7c1062]::panicking::begin_panic<rustc_errors[b882cf8cc0f2d9b3]::ExplicitBug>::{closure#0}, !>
  14:     0x7fa27137bfff - std[93bbb3cd3e7c1062]::panicking::begin_panic::<rustc_errors[b882cf8cc0f2d9b3]::ExplicitBug>
  15:     0x7fa271388f16 - std[93bbb3cd3e7c1062]::panic::panic_any::<rustc_errors[b882cf8cc0f2d9b3]::ExplicitBug>
  16:     0x7fa27138a6f3 - <rustc_errors[b882cf8cc0f2d9b3]::HandlerInner>::bug
  17:     0x7fa27138a150 - <rustc_errors[b882cf8cc0f2d9b3]::Handler>::bug
  18:     0x7fa2712c68b6 - rustc_middle[c43c5dddfafcfdf0]::ty::context::tls::with_opt::<rustc_middle[c43c5dddfafcfdf0]::util::bug::opt_span_bug_fmt<rustc_span[5a327fbd7b70632c]::span_encoding::Span>::{closure#0}, ()>
  19:     0x7fa2712c9946 - rustc_middle[c43c5dddfafcfdf0]::util::bug::opt_span_bug_fmt::<rustc_span[5a327fbd7b70632c]::span_encoding::Span>
  20:     0x7fa2712c98b3 - rustc_middle[c43c5dddfafcfdf0]::util::bug::bug_fmt
  21:     0x7fa2720a35ee - <rustc_data_structures[4e1b415330f15730]::intern::Interned<rustc_middle[c43c5dddfafcfdf0]::ty::sty::RegionKind> as rustc_data_structures[4e1b415330f15730]::stable_hasher::HashStable<rustc_query_system[7e1ef711748c1dc0]::ich::hcx::StableHashingContext>>::hash_stable
  22:     0x7fa2720ec69f - <rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnv as rustc_data_structures[4e1b415330f15730]::stable_hasher::HashStable<rustc_query_system[7e1ef711748c1dc0]::ich::hcx::StableHashingContext>>::hash_stable
  23:     0x7fa271c3bf1e - <rustc_query_system[7e1ef711748c1dc0]::query::config::QueryVtable<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::Ty>, bool>>::to_dep_node
  24:     0x7fa271ba757f - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::try_execute_query::<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_query_system[7e1ef711748c1dc0]::query::caches::DefaultCache<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::Ty>, bool>>
  25:     0x7fa27267f4fb - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::get_query::<rustc_query_impl[5eb223aa473b54b7]::queries::is_sized_raw, rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt>
  26:     0x7fa2720e2335 - <rustc_middle[c43c5dddfafcfdf0]::ty::Ty>::is_sized
  27:     0x7fa271eebcfa - rustc_trait_selection[d05df1b49be1ed2e]::traits::project::opt_normalize_projection_type
  28:     0x7fa272916a08 - rustc_trait_selection[d05df1b49be1ed2e]::traits::project::normalize_projection_type
  29:     0x7fa2725a8433 - <rustc_infer[130c9cf43637d4b6]::infer::InferCtxtBuilder as rustc_trait_selection[d05df1b49be1ed2e]::infer::InferCtxtBuilderExt>::enter_canonical_trait_query::<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::sty::ProjectionTy>, rustc_middle[c43c5dddfafcfdf0]::traits::query::NormalizationResult, rustc_traits[6d6289cb5976f7ed]::normalize_projection_ty::normalize_projection_ty::{closure#0}>
  30:     0x7fa2725afe17 - rustc_traits[6d6289cb5976f7ed]::normalize_projection_ty::normalize_projection_ty
  31:     0x7fa2726e949f - <rustc_query_system[7e1ef711748c1dc0]::dep_graph::graph::DepGraph<rustc_middle[c43c5dddfafcfdf0]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c43c5dddfafcfdf0]::ty::context::TyCtxt, rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::sty::ProjectionTy>>, core[c7f008e1dcb6080]::result::Result<&rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::QueryResponse<rustc_middle[c43c5dddfafcfdf0]::traits::query::NormalizationResult>>, rustc_middle[c43c5dddfafcfdf0]::traits::query::NoSolution>>
  32:     0x7fa272621a08 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::try_execute_query::<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_query_system[7e1ef711748c1dc0]::query::caches::DefaultCache<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::sty::ProjectionTy>>, core[c7f008e1dcb6080]::result::Result<&rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::QueryResponse<rustc_middle[c43c5dddfafcfdf0]::traits::query::NormalizationResult>>, rustc_middle[c43c5dddfafcfdf0]::traits::query::NoSolution>>>
  33:     0x7fa27268da78 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::get_query::<rustc_query_impl[5eb223aa473b54b7]::queries::normalize_projection_ty, rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt>
  34:     0x7fa272750788 - <rustc_query_impl[5eb223aa473b54b7]::Queries as rustc_middle[c43c5dddfafcfdf0]::ty::query::QueryEngine>::normalize_projection_ty
  35:     0x7fa271f205e7 - <rustc_trait_selection[d05df1b49be1ed2e]::traits::query::normalize::QueryNormalizer as rustc_middle[c43c5dddfafcfdf0]::ty::fold::FallibleTypeFolder>::try_fold_ty
  36:     0x7fa271a9bf7a - <rustc_infer[130c9cf43637d4b6]::infer::InferCtxtBuilder>::enter_with_canonical::<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::Ty>, core[c7f008e1dcb6080]::result::Result<&rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::QueryResponse<rustc_middle[c43c5dddfafcfdf0]::traits::query::DropckOutlivesResult>>, rustc_middle[c43c5dddfafcfdf0]::traits::query::NoSolution>, rustc_traits[6d6289cb5976f7ed]::dropck_outlives::dropck_outlives::{closure#0}>
  37:     0x7fa2725acb2b - rustc_traits[6d6289cb5976f7ed]::dropck_outlives::dropck_outlives
  38:     0x7fa2726e8457 - <rustc_query_system[7e1ef711748c1dc0]::dep_graph::graph::DepGraph<rustc_middle[c43c5dddfafcfdf0]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c43c5dddfafcfdf0]::ty::context::TyCtxt, rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::Ty>>, core[c7f008e1dcb6080]::result::Result<&rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::QueryResponse<rustc_middle[c43c5dddfafcfdf0]::traits::query::DropckOutlivesResult>>, rustc_middle[c43c5dddfafcfdf0]::traits::query::NoSolution>>
  39:     0x7fa272620aa5 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::try_execute_query::<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_query_system[7e1ef711748c1dc0]::query::caches::DefaultCache<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::ty::ParamEnvAnd<rustc_middle[c43c5dddfafcfdf0]::ty::Ty>>, core[c7f008e1dcb6080]::result::Result<&rustc_middle[c43c5dddfafcfdf0]::infer::canonical::Canonical<rustc_middle[c43c5dddfafcfdf0]::infer::canonical::QueryResponse<rustc_middle[c43c5dddfafcfdf0]::traits::query::DropckOutlivesResult>>, rustc_middle[c43c5dddfafcfdf0]::traits::query::NoSolution>>>
  40:     0x7fa272683474 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::get_query::<rustc_query_impl[5eb223aa473b54b7]::queries::dropck_outlives, rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt>
  41:     0x7fa2727507dc - <rustc_query_impl[5eb223aa473b54b7]::Queries as rustc_middle[c43c5dddfafcfdf0]::ty::query::QueryEngine>::dropck_outlives
  42:     0x7fa271f2f065 - <rustc_infer[130c9cf43637d4b6]::infer::at::At as rustc_trait_selection[d05df1b49be1ed2e]::traits::query::dropck_outlives::AtExt>::dropck_outlives
  43:     0x7fa27174ed4d - <rustc_typeck[435f3367231454a0]::check::regionck::RegionCtxt as rustc_hir[9824cce51557701d]::intravisit::Visitor>::visit_expr
  44:     0x7fa2717502ce - <rustc_typeck[435f3367231454a0]::check::regionck::RegionCtxt as rustc_hir[9824cce51557701d]::intravisit::Visitor>::visit_expr
  45:     0x7fa27174dfd5 - <rustc_typeck[435f3367231454a0]::check::regionck::RegionCtxt>::visit_fn_body
  46:     0x7fa2716b5b4c - <rustc_typeck[435f3367231454a0]::check::fn_ctxt::FnCtxt>::regionck_fn
  47:     0x7fa27172e533 - <rustc_infer[130c9cf43637d4b6]::infer::InferCtxtBuilder>::enter::<&rustc_middle[c43c5dddfafcfdf0]::ty::context::TypeckResults, <rustc_typeck[435f3367231454a0]::check::inherited::InheritedBuilder>::enter<rustc_typeck[435f3367231454a0]::check::typeck_with_fallback<rustc_typeck[435f3367231454a0]::check::typeck::{closure#0}>::{closure#1}, &rustc_middle[c43c5dddfafcfdf0]::ty::context::TypeckResults>::{closure#0}>
  48:     0x7fa2717143af - rustc_typeck[435f3367231454a0]::check::typeck
  49:     0x7fa2726f0710 - <rustc_query_system[7e1ef711748c1dc0]::dep_graph::graph::DepGraph<rustc_middle[c43c5dddfafcfdf0]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c43c5dddfafcfdf0]::ty::context::TyCtxt, rustc_span[5a327fbd7b70632c]::def_id::LocalDefId, &rustc_middle[c43c5dddfafcfdf0]::ty::context::TypeckResults>
  50:     0x7fa271bc25d5 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::try_execute_query::<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_query_system[7e1ef711748c1dc0]::query::caches::DefaultCache<rustc_span[5a327fbd7b70632c]::def_id::LocalDefId, &rustc_middle[c43c5dddfafcfdf0]::ty::context::TypeckResults>>
  51:     0x7fa271ca1ed8 - <rustc_query_impl[5eb223aa473b54b7]::Queries as rustc_middle[c43c5dddfafcfdf0]::ty::query::QueryEngine>::typeck
  52:     0x7fa27176f60c - <rustc_middle[c43c5dddfafcfdf0]::hir::map::Map>::par_body_owners::<rustc_typeck[435f3367231454a0]::check::typeck_item_bodies::{closure#0}>
  53:     0x7fa27241058c - rustc_typeck[435f3367231454a0]::check::typeck_item_bodies
  54:     0x7fa27270e613 - <rustc_query_system[7e1ef711748c1dc0]::dep_graph::graph::DepGraph<rustc_middle[c43c5dddfafcfdf0]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c43c5dddfafcfdf0]::ty::context::TyCtxt, (), ()>
  55:     0x7fa27265e4bf - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::try_execute_query::<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_query_system[7e1ef711748c1dc0]::query::caches::DefaultCache<(), ()>>
  56:     0x7fa272686b01 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::get_query::<rustc_query_impl[5eb223aa473b54b7]::queries::typeck_item_bodies, rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt>
  57:     0x7fa2724131e3 - <rustc_session[62db8dbcb5f03131]::session::Session>::time::<(), rustc_typeck[435f3367231454a0]::check_crate::{closure#7}>
  58:     0x7fa272410b93 - rustc_typeck[435f3367231454a0]::check_crate
  59:     0x7fa2721978f7 - rustc_interface[a6e240183aba3d57]::passes::analysis
  60:     0x7fa27270a7f5 - <rustc_query_system[7e1ef711748c1dc0]::dep_graph::graph::DepGraph<rustc_middle[c43c5dddfafcfdf0]::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle[c43c5dddfafcfdf0]::ty::context::TyCtxt, (), core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>
  61:     0x7fa272654502 - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::try_execute_query::<rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt, rustc_query_system[7e1ef711748c1dc0]::query::caches::DefaultCache<(), core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>>
  62:     0x7fa27269566e - rustc_query_system[7e1ef711748c1dc0]::query::plumbing::get_query::<rustc_query_impl[5eb223aa473b54b7]::queries::analysis, rustc_query_impl[5eb223aa473b54b7]::plumbing::QueryCtxt>
  63:     0x7fa2721732a7 - <rustc_interface[a6e240183aba3d57]::passes::QueryContext>::enter::<rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}::{closure#2}::{closure#3}, core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>
  64:     0x7fa272150cb8 - <rustc_interface[a6e240183aba3d57]::interface::Compiler>::enter::<rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}::{closure#2}, core[c7f008e1dcb6080]::result::Result<core[c7f008e1dcb6080]::option::Option<rustc_interface[a6e240183aba3d57]::queries::Linker>, rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>
  65:     0x7fa272163d0f - rustc_span[5a327fbd7b70632c]::with_source_map::<core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>, rustc_interface[a6e240183aba3d57]::interface::create_compiler_and_run<core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>, rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}>::{closure#1}>
  66:     0x7fa272162b94 - rustc_interface[a6e240183aba3d57]::interface::create_compiler_and_run::<core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>, rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}>
  67:     0x7fa27214e6b2 - <scoped_tls[3e920f98e8d1f9d2]::ScopedKey<rustc_span[5a327fbd7b70632c]::SessionGlobals>>::set::<rustc_interface[a6e240183aba3d57]::interface::run_compiler<core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>, rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}>::{closure#0}, core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>
  68:     0x7fa27214ca1f - std[93bbb3cd3e7c1062]::sys_common::backtrace::__rust_begin_short_backtrace::<rustc_interface[a6e240183aba3d57]::util::run_in_thread_pool_with_globals<rustc_interface[a6e240183aba3d57]::interface::run_compiler<core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>, rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}>::{closure#0}, core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>::{closure#0}, core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>
  69:     0x7fa272164ca2 - <<std[93bbb3cd3e7c1062]::thread::Builder>::spawn_unchecked_<rustc_interface[a6e240183aba3d57]::util::run_in_thread_pool_with_globals<rustc_interface[a6e240183aba3d57]::interface::run_compiler<core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>, rustc_driver[dfa02f50b2a2e61e]::run_compiler::{closure#1}>::{closure#0}, core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>::{closure#0}, core[c7f008e1dcb6080]::result::Result<(), rustc_errors[b882cf8cc0f2d9b3]::ErrorGuaranteed>>::{closure#1} as core[c7f008e1dcb6080]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0}
  70:     0x7fa26faaaf83 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hd51c3662b34e3fa5
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/alloc/src/boxed.rs:1861:9
  71:     0x7fa26faaaf83 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb373dd9df6b8a0f7
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/alloc/src/boxed.rs:1861:9
  72:     0x7fa26faaaf83 - std::sys::unix::thread::Thread::new::thread_start::h987e16b384dce900
                               at /rustc/63b8f01bb5ca277e7df8d7efe094ed4244c1790c/library/std/src/sys/unix/thread.rs:108:17
  73:     0x7fa26f8835c2 - start_thread
  74:     0x7fa26f908584 - __clone
  75:                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 1.61.0-nightly (63b8f01bb 2022-03-24) running on x86_64-unknown-linux-gnu

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

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

query stack during panic:
#0 [normalize_projection_ty] normalizing `Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [Binder(TraitPredicate(<B as Bar>, polarity:Positive), []), Binder(TraitPredicate(<B as core::marker::Sized>, polarity:Positive), []), Binder(OutlivesPredicate(B, ReLateBound(DebruijnIndex(1), BoundRegion { var: 0, kind: BrAnon(0) })), [])], reveal: UserFacing, constness: NotConst }, value: ProjectionTy { substs: [T], item_def_id: DefId(2:2092 ~ core[c7f0]::ptr::metadata::Pointee::Metadata) } } }`
#1 [dropck_outlives] computing dropck types for `Canonical { max_universe: U0, variables: [CanonicalVarInfo { kind: Region(U0) }], value: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [Binder(TraitPredicate(<B as Bar>, polarity:Positive), []), Binder(TraitPredicate(<B as core::marker::Sized>, polarity:Positive), []), Binder(OutlivesPredicate(B, ReLateBound(DebruijnIndex(1), BoundRegion { var: 0, kind: BrAnon(0) })), [])], reveal: UserFacing, constness: NotConst }, value: <T as core::ptr::metadata::Pointee>::Metadata } }`
#2 [typeck] type-checking `<impl at src/main.rs:9:1: 13:2>::foo`
#3 [typeck_item_bodies] type-checking all item bodies
#4 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `foo`

I ran a quick cargo-bisect:

searched nightlies: from nightly-2022-03-01 to nightly-2022-03-24
regressed nightly: nightly-2022-03-16
searched commits: from 285fa7e to 52b3455
regressed commit: 2184c7c

bisected with cargo-bisect-rustc v0.6.0

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

cargo bisect-rustc 

The offending line is the std::ptr::metadata(), so we should probably tag this with the appropriate feature tag.

(Sorry if I messed anything up, I'm completely new to Rust ICE bug reports!)

[compiler-errors]

probably due to my PR #93977

@rustbot claim

[dimpolo]

I get the same error on code that I got minimized to:

#![feature(ptr_metadata)]

use core::marker::PhantomData;
use core::ops::Deref;
use core::ptr::{DynMetadata, Pointee};

struct Foo<T> {
    bar: PhantomData<T>,
}

impl<T> Deref for Foo<T>
where
    T: Pointee<Metadata = DynMetadata<T>> + 'static,
{
    type Target = T;

    fn deref(&self) -> &Self::Target {
        self.some_method()
    }
}

[usamoi]

Same error with this example:

#![feature(ptr_metadata)]

use std::ptr::Pointee;

unsafe fn ice<T: ?Sized + 'static>(ptr: *const T) -> <T as Pointee>::Metadata {
    std::ptr::metadata(ptr)
}

[maximveligan]

Same error I got with this example

#![feature(ptr_metadata)]

fn bar<U: 'static + ?Sized>() -> <U as core::ptr::Pointee>::Metadata {panic!()}

Defining it in a trait is fine though

#![feature(ptr_metadata)]

trait Foo {
    fn bar<U: 'static + ?Sized>() -> <U as core::ptr::Pointee>::Metadata;
}

But adding a function body results in a crash

#![feature(ptr_metadata)]

trait Foo {
    fn bar<U: 'static + ?Sized>() -> <U as core::ptr::Pointee>::Metadata { panic!() }
}