paste

thread 'rustc' panicked at 'called `Option::unwrap()` on a `None` value', /Users/alex/Software/rust-devel/src/libcore/macros.rs:41:40
stack backtrace:
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::default_hook
   5: rustc_driver::report_ice
   6: std::panicking::rust_panic_with_hook
   7: std::panicking::continue_panic_fmt
   8: rust_begin_unwind
   9: core::panicking::panic_fmt
  10: core::panicking::panic
  11: rustc::traits::select::SelectionContext::confirm_candidate
  12: rustc::traits::select::SelectionContext::select
  13: rustc_data_structures::obligation_forest::ObligationForest<O>::process_obligations
  14: <rustc::traits::fulfill::FulfillmentContext as rustc::traits::engine::TraitEngine>::select_where_possible
  15: rustc_typeck::check::FnCtxt::select_obligations_where_possible
  16: rustc_typeck::check::FnCtxt::resolve_vars_with_obligations
  17: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  18: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  19: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_has_type_or_error
  20: rustc_typeck::check::_match::<impl rustc_typeck::check::FnCtxt>::check_match
  21: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  22: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  23: rustc_typeck::check::FnCtxt::with_breakable_ctxt
  24: rustc_typeck::check::FnCtxt::check_block_with_expected
  25: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  26: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  27: rustc_typeck::check::FnCtxt::check_stmt
  28: rustc_typeck::check::FnCtxt::with_breakable_ctxt
  29: rustc_typeck::check::FnCtxt::check_block_with_expected
  30: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  31: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  32: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  33: rustc_typeck::check::check_fn
  34: rustc::ty::context::tls::with_context::{{closure}}
  35: rustc::ty::context::GlobalCtxt::enter_local
  36: rustc_typeck::check::typeck_tables_of
  37: rustc::ty::query::__query_compute::typeck_tables_of
  38: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  39: rustc::dep_graph::graph::DepGraph::with_task_impl
  40: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  41: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
  42: rustc_typeck::check::typeck_item_bodies
  43: rustc::ty::query::__query_compute::typeck_item_bodies
  44: rustc::dep_graph::graph::DepGraph::with_task_impl
  45: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  46: rustc::util::common::time
  47: rustc_typeck::check_crate
  48: rustc_interface::passes::analysis
  49: rustc::ty::query::__query_compute::analysis
  50: rustc::dep_graph::graph::DepGraph::with_task_impl
  51: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  52: rustc::ty::context::tls::enter_global
  53: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
  54: rustc_interface::passes::create_global_ctxt::{{closure}}
  55: rustc_interface::passes::BoxedGlobalCtxt::enter
  56: rustc_interface::interface::run_compiler_in_existing_thread_pool
  57: std::thread::local::LocalKey<T>::with
  58: scoped_tls::ScopedKey<T>::set
  59: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

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