ICE in nightly when using trying to preserve rand::rngs::ThreadRng across awaits

[vi]

rustc 1.41.0-nightly (3eeb8d4f2 2019-12-12)

error: internal compiler error: src/librustc/hir/map/mod.rs:1031: no name for expr move ||
...
  15: rustc_errors::HandlerInner::bug
  16: rustc_errors::Handler::bug
  17: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  18: rustc::ty::context::tls::with_opt::{{closure}}
  19: rustc::ty::context::tls::with_opt
  20: rustc::util::bug::opt_span_bug_fmt
  21: rustc::util::bug::bug_fmt
  22: rustc::hir::map::Map::name
  23: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt>::note_obligation_cause
  24: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt>::report_selection_error
  25: rustc::traits::error_reporting::<impl rustc::infer::InferCtxt>::report_fulfillment_errors
  26: rustc_typeck::check::FnCtxt::resolve_generator_interiors
  27: rustc::ty::context::tls::with_context::{{closure}}
  28: rustc_typeck::check::typeck_tables_of
  29: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  30: rustc::dep_graph::graph::DepGraph::with_task_impl
  31: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::force_query
  32: rustc::ty::query::plumbing::force_from_dep_node
  33: rustc::dep_graph::graph::DepGraph::try_mark_previous_green
  34: rustc::dep_graph::graph::DepGraph::try_mark_green
  35: rustc::dep_graph::graph::DepGraph::try_mark_green_and_read
  36: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  37: rustc_typeck::collect::type_of
  38: rustc::ty::query::__query_compute::type_of
  39: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::type_of>::compute
  40: rustc::dep_graph::graph::DepGraph::with_task_impl
  41: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  42: rustc::hir::intravisit::walk_expr
  43: rustc::hir::intravisit::Visitor::visit_fn
  44: rustc::hir::intravisit::walk_item
  45: <rustc_typeck::collect::CollectItemTypesVisitor as rustc::hir::intravisit::Visitor>::visit_item
  46: rustc::hir::map::Map::visit_item_likes_in_module
  47: rustc_typeck::collect::collect_mod_item_types
  48: rustc::ty::query::__query_compute::collect_mod_item_types
  49: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::collect_mod_item_types>::compute
  50: rustc::dep_graph::graph::DepGraph::with_task_impl
  51: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  52: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query
  53: rustc_typeck::check_crate::{{closure}}::{{closure}}
  54: rustc::util::common::time
  55: rustc_typeck::check_crate
  56: rustc_interface::passes::analysis
  57: rustc::ty::query::__query_compute::analysis
  58: rustc::dep_graph::graph::DepGraph::with_task_impl
  59: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  60: rustc::ty::context::tls::enter_global
  61: rustc_interface::interface::run_compiler_in_existing_thread_pool
  62: std::thread::local::LocalKey<T>::with
  63: scoped_tls::ScopedKey<T>::set
  64: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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 1.41.0-nightly (3eeb8d4f2 2019-12-12) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental -C link-arg=-fuse-ld=lld --crate-type bin

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

query stack during panic:
#0 [typeck_tables_of] processing `client::client`
#1 [typeck_tables_of] processing `client::client::{{closure}}#0`
#2 [type_of] processing `client::client::{{closure}}#0`
#3 [collect_mod_item_types] collecting item types in module `client`
#4 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to previous error

error: could not compile `natram`.

Source code: vi/natram@d9cadb2

Full log: rustcbug.txt

Stable Rust correctly shows error:

248 |     tokio::spawn(async move {
    |     ^^^^^^^^^^^^ `std::ptr::NonNull<rand::rngs::adapter::reseeding::ReseedingRng<rand_chacha::chacha::ChaCha20Core, rand_core::os::OsRng>>` cannot be sent between threads safely

(although further message is rather big).

[csmoe]

Fixed by #67289