ICE on 1.56.0-nightly: StableHasher: unexpected region RePlaceholder(...)

[nicholasfagan]

Code

struct HasLifetime<'a>(core::marker::PhantomData<&'a u32>);
struct Wrap<T: for<'a> FnMut(HasLifetime<'a>)>(T);
fn doesnt_satisfy_requirements<'a>(args: HasLifetime<'a>) {}
// isn't send or sync, also an &dyn FnMut doesn't satisfy FnMut.
static STATIC_OR_CONST_VAR: Wrap<&'static dyn for<'a> FnMut(HasLifetime<'a>)> = Wrap(&doesnt_satisfy_requirements);

Meta

rustc +nightly --version --verbose:

rustc 1.56.0-nightly (ad981d58e 2021-08-08)
binary: rustc
commit-hash: ad981d58e1ca16bcf4072577934630deb11c5e14
commit-date: 2021-08-08
host: x86_64-unknown-linux-gnu
release: 1.56.0-nightly
LLVM version: 12.0.1

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

Error output

error: internal compiler error: compiler/rustc_middle/src/ich/impls_ty.rs:94:17: StableHasher: unexpected region RePlaceholder(Placeholder { universe: U1, name: BrNamed(DefId(0:10 ~ ice[14c8]::Wrap::'a), 'a) })

Backtrace

thread 'rustc' panicked at 'Box<dyn Any>', compiler/rustc_errors/src/lib.rs:1046:9
stack backtrace:
   0: std::panicking::begin_panic
   1: std::panic::panic_any
   2: rustc_errors::HandlerInner::bug
   3: rustc_errors::Handler::bug
   4: rustc_middle::ty::context::tls::with_opt
   5: rustc_middle::util::bug::opt_span_bug_fmt
   6: rustc_middle::util::bug::bug_fmt
   7: rustc_middle::ich::impls_ty::<impl rustc_data_structures::stable_hasher::HashStable<rustc_middle::ich::hcx::StableHashingContext> for rustc_middle::ty::sty::RegionKind>::hash_stable
   8: std::thread::local::LocalKey<T>::with
   9: <rustc_middle::ty::TyS as rustc_data_structures::stable_hasher::HashStable<rustc_middle::ich::hcx::StableHashingContext>>::hash_stable
  10: std::thread::local::LocalKey<T>::with
  11: <rustc_middle::ty::TyS as rustc_data_structures::stable_hasher::HashStable<rustc_middle::ich::hcx::StableHashingContext>>::hash_stable
  12: std::thread::local::LocalKey<T>::with
  13: rustc_middle::ich::impls_ty::<impl rustc_data_structures::stable_hasher::HashStable<rustc_middle::ich::hcx::StableHashingContext> for rustc_middle::ty::sty::Binder<T>>::hash_stable
  14: <T as rustc_query_system::dep_graph::dep_node::DepNodeParams<Ctxt>>::to_fingerprint
  15: rustc_query_system::query::config::QueryVtable<CTX,K,V>::to_dep_node
  16: rustc_query_system::query::plumbing::get_query_impl
  17: rustc_query_system::query::plumbing::get_query
  18: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtExt>::report_selection_error
  19: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtPrivExt>::report_fulfillment_error
  20: <rustc_infer::infer::InferCtxt as rustc_trait_selection::traits::error_reporting::InferCtxtExt>::report_fulfillment_errors
  21: rustc_typeck::check::fn_ctxt::_impl::<impl rustc_typeck::check::fn_ctxt::FnCtxt>::select_all_obligations_or_error
  22: rustc_infer::infer::InferCtxtBuilder::enter
  23: rustc_typeck::check::wfcheck::check_item_well_formed
  24: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  25: rustc_data_structures::stack::ensure_sufficient_stack
  26: rustc_query_system::query::plumbing::force_query_with_job
  27: rustc_query_system::query::plumbing::get_query_impl
  28: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::check_item_well_formed
  29: <rustc_typeck::check::wfcheck::CheckTypeWellFormedVisitor as rustc_hir::intravisit::Visitor>::visit_item
  30: std::panicking::try
  31: rustc_data_structures::sync::par_for_each_in
  32: rustc_session::session::Session::track_errors
  33: rustc_typeck::check_crate
  34: rustc_interface::passes::analysis
  35: rustc_middle::dep_graph::<impl rustc_query_system::dep_graph::DepKind for rustc_middle::dep_graph::dep_node::DepKind>::with_deps
  36: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
  37: rustc_query_system::dep_graph::graph::DepGraph<K>::with_eval_always_task
  38: rustc_data_structures::stack::ensure_sufficient_stack
  39: rustc_query_system::query::plumbing::force_query_with_job
  40: rustc_query_system::query::plumbing::get_query_impl
  41: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
  42: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
  43: rustc_span::with_source_map
  44: rustc_interface::interface::create_compiler_and_run
  45: scoped_tls::ScopedKey<T>::set

[nicholasfagan]

Related ICE

Possible related to #77708

[Aaron1011]

This should be fixed by #87811

[nicholasfagan]

This is solved in 1.56.1. Closing.