failing

thread 'rustc' panicked at 'assertion failed: !infcx.is_there_snapshot.get()', src/librustc/traits/fulfill.rs:173
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: rustc::traits::fulfill::FulfillmentContext::register_predicate_obligation
   1: rustc_typeck::check::FnCtxt::register_predicate
   2: rustc_typeck::check::FnCtxt::add_obligations_for_parameters
   3: rustc_typeck::check::method::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::lookup_method_in_trait_adjusted
   4: rustc_typeck::check::autoderef::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::try_overloaded_deref
   5: rustc_typeck::check::autoderef::Autoderef::finalize_as_infer_ok
   6: rustc_typeck::check::coercion::Coerce::coerce
   7: rustc_typeck::check::coercion::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::try_coerce
   8: rustc_typeck::check::demand::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::demand_coerce
   9: rustc_typeck::check::FnCtxt::check_argument_types
  10: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::confirm_builtin_call
  11: rustc_typeck::check::callee::<impl rustc_typeck::check::FnCtxt<'a, 'gcx, 'tcx>>::check_call
  12: rustc_typeck::check::FnCtxt::check_expr_kind
  13: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_lvalue_pref
  14: rustc_typeck::check::FnCtxt::check_decl_initializer
  15: rustc_typeck::check::FnCtxt::check_decl_local
  16: rustc_typeck::check::FnCtxt::check_stmt
  17: rustc_typeck::check::FnCtxt::check_block_with_expected::{{closure}}
  18: rustc_typeck::check::FnCtxt::check_block_with_expected
  19: rustc_typeck::check::FnCtxt::check_expr_kind
  20: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_lvalue_pref
  21: rustc_typeck::check::FnCtxt::check_block_with_expected::{{closure}}
  22: rustc_typeck::check::FnCtxt::check_block_with_expected
  23: rustc_typeck::check::FnCtxt::check_expr_kind
  24: rustc_typeck::check::FnCtxt::check_expr_with_expectation_and_lvalue_pref
  25: rustc_typeck::check::FnCtxt::check_return_expr
  26: rustc_typeck::check::check_fn
  27: rustc_typeck::check::typeck_tables
  28: rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables<'tcx>>::try_get
  29: rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_tables<'tcx>>::get
  30: rustc::ty::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::item_tables
  31: rustc_typeck::check::typeck_item_bodies
  32: rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_item_bodies<'tcx>>::try_get
  33: rustc::ty::maps::<impl rustc::ty::maps::queries::typeck_item_bodies<'tcx>>::get
  34: rustc_typeck::check_crate
  35: rustc_driver::driver::phase_3_run_analysis_passes::{{closure}}
  36: rustc_driver::driver::phase_3_run_analysis_passes
  37: rustc_driver::driver::compile_input
  38: rustc_driver::run_compiler
  39: std::panicking::try::do_call
  40: __rust_maybe_catch_panic
  41: <F as alloc::boxed::FnBox<A>>::call_box
  42: std::sys::imp::thread::Thread::new::thread_start
  43: _pthread_body
  44: _pthread_start

error: Could not compile `collections`.