Rustc ICE

```shell
cd thespis_impl
cargo check
```

    Checking thespis_impl v0.1.0 (/data/doc/code/thespis/thespis_impl)
error: internal compiler error: src/librustc_mir/borrow_check/nll/universal_regions.rs:741: cannot convert `ReEmpty` to a region vid

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:635:9
stack backtrace:
   0:     0x7fe910466dc3 - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::h031f3165295127aa
                               at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1:     0x7fe91045ec4b - std::sys_common::backtrace::_print::h8298470433024baa
                               at src/libstd/sys_common/backtrace.rs:71
   2:     0x7fe910463026 - std::panicking::default_hook::{{closure}}::hab8b04c136da660a
                               at src/libstd/sys_common/backtrace.rs:59
                               at src/libstd/panicking.rs:197
   3:     0x7fe910462db9 - std::panicking::default_hook::h3a0b8aa0a6dcb151
                               at src/libstd/panicking.rs:211
   4:     0x7fe90e2047a0 - rustc::util::common::panic_hook::h84d3475bdc604207
   5:     0x7fe910463818 - std::panicking::rust_panic_with_hook::h8a2f19cc4c54a07c
                               at src/libstd/panicking.rs:478
   6:     0x7fe90cddb68c - std::panicking::begin_panic::h028f5e735aa88eae
   7:     0x7fe90cdf54ce - rustc_errors::Handler::bug::hf8e60c8dc5020d24
   8:     0x7fe90e0761c2 - rustc::util::bug::opt_span_bug_fmt::{{closure}}::h9d4c68d1d343828f
   9:     0x7fe90e073139 - rustc::ty::context::tls::with_opt::{{closure}}::h3d0b0a087a7582b4
  10:     0x7fe90e073054 - rustc::ty::context::tls::with_context_opt::h6da57694e326ee0b
  11:     0x7fe90e0730e6 - rustc::ty::context::tls::with_opt::he0674a7a0de7d093
  12:     0x7fe90e0760d7 - rustc::util::bug::opt_span_bug_fmt::h5105cb49dae5802a
  13:     0x7fe90e076041 - rustc::util::bug::bug_fmt::he9b940cfc89c678a
  14:     0x7fe90ea0a5a1 - rustc_mir::borrow_check::nll::universal_regions::UniversalRegionIndices::to_region_vid::{{closure}}::h31fa0405ce76d844
  15:     0x7fe90ea0a539 - rustc_mir::borrow_check::nll::universal_regions::UniversalRegionIndices::to_region_vid::h822d32ee07e41940
  16:     0x7fe90eb536c6 - <&mut rustc_mir::borrow_check::nll::type_check::constraint_conversion::ConstraintConversion as rustc::infer::outlives::obligations::TypeOutlivesDelegate>::push_verify::h9879b0a189d955da
  17:     0x7fe90e928d2e - rustc::infer::outlives::obligations::TypeOutlives<D>::projection_must_outlive::hf6106b8d6e8333bc
  18:     0x7fe90e9287a5 - rustc::infer::outlives::obligations::TypeOutlives<D>::components_must_outlive::h46f9f03b60cfe506
  19:     0x7fe90e928350 - rustc::infer::outlives::obligations::TypeOutlives<D>::type_must_outlive::hbb042cfdc3396ecc
  20:     0x7fe90eb53198 - rustc_mir::borrow_check::nll::type_check::constraint_conversion::ConstraintConversion::convert_all::h39d754763afea387
  21:     0x7fe90e8f69b4 - rustc_mir::borrow_check::nll::type_check::TypeChecker::prove_predicate::hd51d07d509a1171b
  22:     0x7fe90e8f661f - rustc_mir::borrow_check::nll::type_check::TypeChecker::normalize_and_prove_instantiated_predicates::hfadc723aa2fc7e0e
  23:     0x7fe90e8f3c62 - rustc_mir::borrow_check::nll::type_check::TypeChecker::check_rvalue::hf88f7f0abdc4205a
  24:     0x7fe90e8f743a - rustc_mir::borrow_check::nll::type_check::TypeChecker::typeck_mir::h4f8ceba44dc96183
  25:     0x7fe90e8ead28 - rustc_mir::borrow_check::nll::type_check::type_check::hd1563735dd19d474
  26:     0x7fe90e992e7a - rustc_mir::borrow_check::nll::compute_regions::h11cf9b4100871537
  27:     0x7fe90ea4dc3d - rustc_mir::borrow_check::do_mir_borrowck::h600234233b498560
  28:     0x7fe90eb397d3 - rustc::ty::context::GlobalCtxt::enter_local::he4a1042e218ebb02
  29:     0x7fe90ea4d3ab - rustc_mir::borrow_check::mir_borrowck::h2a2fcffe65503db3
  30:     0x7fe90fed7056 - rustc::ty::query::__query_compute::mir_borrowck::h3266d58ba0c599fc
  31:     0x7fe90fe2e894 - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::mir_borrowck>::compute::h740cfd4ecbc5a5cd
  32:     0x7fe90fe2a058 - rustc::dep_graph::graph::DepGraph::with_task_impl::hce3ace1a8c6e1ec4
  33:     0x7fe90fe446ae - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::ha4d20ae3876b25ab
  34:     0x7fe90fe2e732 - rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners::h7cd4bbb2556ac19d
  35:     0x7fe90fe1fc27 - rustc::util::common::time::h004eda8c05622f62
  36:     0x7fe90fe6e14a - rustc_interface::passes::analysis::he6a8561a6505a159
  37:     0x7fe91072b795 - rustc::ty::query::__query_compute::analysis::hb1d74b3b065986be
  38:     0x7fe9107728e8 - rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::analysis>::compute::h5c90704fa74b78a9
  39:     0x7fe9107509b2 - rustc::dep_graph::graph::DepGraph::with_task_impl::h0b9fb3d5ff95462d
  40:     0x7fe9107755b1 - rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query::h7e315c5252f1bf7d
  41:     0x7fe91072baa5 - rustc::ty::context::tls::enter_global::h6e39c726a451f61d
  42:     0x7fe910737266 - rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}::h1f3e73c112ecdded
  43:     0x7fe90fec11e4 - rustc_interface::passes::create_global_ctxt::{{closure}}::h96ecd80d8f02eb4c
  44:     0x7fe9107371ee - rustc_interface::passes::BoxedGlobalCtxt::enter::hf2678048729c56fb
  45:     0x7fe9107479f3 - rustc_interface::interface::run_compiler_in_existing_thread_pool::h80e01640c1bd2550
  46:     0x7fe91071c815 - std::thread::local::LocalKey<T>::with::h1d29af37c0300c7d
  47:     0x7fe91077f1f4 - scoped_tls::ScopedKey<T>::set::hcd31602a4fdbc7a8
  48:     0x7fe9107b3901 - syntax::with_globals::h6f9bb4d03b81c38c
  49:     0x7fe91071e550 - std::sys_common::backtrace::__rust_begin_short_backtrace::hd75831c1c8cc1ae1
  50:     0x7fe9104745e9 - __rust_maybe_catch_panic
                               at src/libpanic_unwind/lib.rs:85
  51:     0x7fe9107386b8 - core::ops::function::FnOnce::call_once{{vtable.shim}}::hdec1144d73d6cc23
  52:     0x7fe9104456fe - <alloc::boxed::Box<F> as core::ops::function::FnOnce<A>>::call_once::h8e272ede9df61306
                               at /rustc/3c3d3c1777041200bb7ed7a65b6562d62899778c/src/liballoc/boxed.rs:704
  53:     0x7fe91047325f - std::sys::unix::thread::Thread::new::thread_start::h8527a493afc9a3d3
                               at /rustc/3c3d3c1777041200bb7ed7a65b6562d62899778c/src/liballoc/boxed.rs:704
                               at src/libstd/sys_common/thread.rs:13
                               at src/libstd/sys/unix/thread.rs:79
  54:     0x7fe9103a2a9c - start_thread
  55:     0x7fe9102c3af2 - clone
  56:                0x0 - <unknown>
query stack during panic:
#0 [mir_borrowck] processing `<multi_thread::address::Addr<A> as thespis::recipient::Recipient<M>>::send`
#1 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.36.0-nightly (3c3d3c177 2019-04-17) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z external-macro-backtrace -C debuginfo=2 -C incremental --crate-type lib

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

error: Could not compile `thespis_impl`.

To learn more, run the command again with --verbose.

Author: najamelan