stack_backtrace

stack backtrace:
   0:     0x7f201dc24e83 - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::h424c732cdce29f94
                               at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1:     0x7f201dc1c804 - std::sys_common::backtrace::_print::h5d4303b538d20e0a
                               at libstd/sys_common/backtrace.rs:71
   2:     0x7f201dc21a30 - std::panicking::default_hook::{{closure}}::h1e99cea75e6d3b3c
                               at libstd/sys_common/backtrace.rs:59
                               at libstd/panicking.rs:380
   3:     0x7f201dc2172b - std::panicking::default_hook::hcecbc1498b4d7dc2
                               at libstd/panicking.rs:396
   4:     0x7f201dc21e9b - std::panicking::rust_panic_with_hook::h31c2e0f7e58cac31
                               at libstd/panicking.rs:576
   5:     0x7f20197e03d8 - std::panicking::begin_panic::h660d249a3761d022
   6:     0x7f2019800e05 - rustc_errors::Handler::bug::h13b2aab548f702cf
   7:     0x7f201a9bb2cf - rustc::session::opt_span_bug_fmt::{{closure}}::h0f5fc813963e7750
   8:     0x7f201a9bb1c1 - rustc::session::opt_span_bug_fmt::hed16f0e719ca27ed
   9:     0x7f201a9bad46 - rustc::session::bug_fmt::hff96d0d0a6319007
  10:     0x7f201c3a8840 - rustc_metadata::cstore_impl::provide_extern::optimized_mir::h2a61c01c2b175129
  11:     0x7f201a8534a7 - rustc::dep_graph::graph::DepGraph::with_task_impl::h5d190914bfee09f2
  12:     0x7f201ab30d93 - rustc::ty::maps::<impl rustc::ty::maps::queries::optimized_mir<'tcx>>::force::ha7d09073ea7fb30b
  13:     0x7f201ab31894 - rustc::ty::maps::<impl rustc::ty::maps::queries::optimized_mir<'tcx>>::try_get::hcd2727561e91f9e0
  14:     0x7f201ac4adda - rustc::ty::maps::TyCtxtAt::optimized_mir::h560ad4c2afa02cfb
  15:     0x7f201aa8cc2d - rustc::ty::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::instance_mir::h6a31505c7b3dd63b
  16:     0x7f201b68f404 - rustc_mir::monomorphize::collector::collect_items_rec::ha9aa8e0fa05b8e1d
  17:     0x7f201b68ebb6 - rustc_mir::monomorphize::collector::collect_crate_mono_items::h5a2d6e24e3a72ea7
  18:     0x7f2013689a94 - rustc_trans::base::collect_and_partition_translation_items::h3de15512759976c5
  19:     0x7f201a86aa3a - rustc::dep_graph::graph::DepGraph::with_task_impl::hc61bfeb0eb2a030a
  20:     0x7f201ac21249 - rustc::ty::maps::<impl rustc::ty::maps::queries::collect_and_partition_translation_items<'tcx>>::force::heca0d3264fd15479
  21:     0x7f201ac218f6 - rustc::ty::maps::<impl rustc::ty::maps::queries::collect_and_partition_translation_items<'tcx>>::try_get::h97e6ce8e5689be7f
  22:     0x7f201ac503c5 - rustc::ty::maps::TyCtxtAt::collect_and_partition_translation_items::h5612b8e8e73bb305
  23:     0x7f201ac4931e - rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::collect_and_partition_translation_items::h54d4299b3516bdd0
  24:     0x7f2013685555 - rustc_trans::base::trans_crate::h432d6225e2e736d9
  25:     0x7f20136e1767 - <rustc_trans::LlvmTransCrate as rustc_trans_utils::trans_crate::TransCrate>::trans_crate::he4c41b5a238a0f84
  26:     0x7f201dfd9d12 - rustc_driver::driver::phase_4_translate_to_llvm::h46635843c07fbe5e
  27:     0x7f201dfd31e1 - rustc_driver::driver::compile_input::{{closure}}::h58c570c938344edf
  28:     0x7f201df64432 - rustc::ty::context::TyCtxt::create_and_enter::ha319f111c46193ec
  29:     0x7f201dfd15d1 - rustc_driver::driver::compile_input::h8ad6c02be74f2f4c
  30:     0x7f201dfed507 - rustc_driver::run_compiler::hdf1d0ce8fc4b1878
  31:     0x7f201df1680a - std::sys_common::backtrace::__rust_begin_short_backtrace::h6f7b2602a31262f9
  32:     0x7f201dc3aede - __rust_maybe_catch_panic
                               at libpanic_unwind/lib.rs:102
  33:     0x7f201df4fc16 - <F as alloc::boxed::FnBox<A>>::call_box::ha5d49eb899421e64
  34:     0x7f201dc3226b - std::sys::unix::thread::Thread::new::thread_start::hfcee115982678f6c
                               at /checkout/src/liballoc/boxed.rs:798
                               at libstd/sys_common/thread.rs:24
                               at libstd/sys/unix/thread.rs:90
  35:     0x7f2018b4108b - start_thread
  36:     0x7f201d8f3e7e - __GI___clone
  37:                0x0 - <unknown>