ICE in ElaborateDrops with generators

[kazimuth]

Repro: https://play.rust-lang.org/?gist=1cebdab1c712e776f255628e150ad93b&version=nightly

#![feature(generators)]

use std::rc::Rc;
use std::cell::RefCell;

fn main() {
    let thing: Rc<RefCell<Option<String>>> = Rc::new(RefCell::new(None));

    let _ = || {
        thing.borrow_mut().unwrap();
        yield;
    };
}

Playground currently panics: rustc 1.25.0-nightly (79a521bb9 2018-01-15) running on x86_64-unknown-linux-gnu. My machine also panics, rustc 1.25.0-nightly (e6072a7b3 2018-01-13) on OSX Yosemite.

Without the yield, this (naturally) gives cannot move out of borrowed content.

Stack trace:

thread 'rustc' panicked at 'called `Result::unwrap()` on an `Err` value: (MoveData { move_paths: [MovePath { place: _0 }, MovePath { place: _1 }, MovePath { place: _2 }, MovePath { place: _3 }, MovePath { place: _4 }, MovePath { place: _5 }, MovePath { place: _6 }, MovePath { place: _7 }, MovePath { place: _8 }, MovePath { place: _9 }, MovePath { place: _10 }, MovePath { place: _11 }], moves: [mp9@bb0[8], mp9@bb1[1], mp7@bb1[2], mp1@bb3[0], mp5@bb4[1], mp5@bb5[1], mp7@bb5[2], mp3@bb5[3], mp6@bb6[0], mp2@bb7[0], mp3@bb8[0], mp3@bb9[0], mp3@bb10[0], mp4@bb10[1], mp6@bb10[2], mp6@bb11[0], mp8@bb11[1], mp11@bb11[4], mp11@bb12[1], mp1@bb12[3], mp1@bb13[0], mp0@bb15[0]], loc_map: LocationMap { map: [[[], [], [], [], [], [], [], [], [mo0]], [[], [mo1], [mo2]], [[]], [[mo3]], [[], [mo4]], [[], [mo5], [mo6], [mo7]], [[mo8]], [[mo9]], [[mo10]], [[mo11]], [[mo12], [mo13], [mo14]], [[mo15], [mo16], [], [], [mo17]], [[], [mo18], [], [mo19]], [[mo20]], [[]], [[mo21]]] }, path_map: [[mo21], [mo3, mo19, mo20], [mo9], [mo7, mo10, mo11, mo12], [mo13], [mo4, mo5], [mo8, mo14, mo15], [mo2, mo6], [mo16], [mo0, mo1], [], [mo17, mo18]], rev_lookup: MovePathLookup { locals: [mp0, mp1, mp2, mp3, mp4, mp5, mp6, mp7, mp8, mp9, mp10, mp11], projections: {} }, inits: [mp1@src/main.rs:9:13: 12:6 (Deep), mp9@src/main.rs:10:9: 10:14 (Deep), mp8@src/main.rs:10:9: 10:14 (NonPanicPathOnly), mp7@src/main.rs:10:9: 10:14 (Deep), mp6@src/main.rs:10:9: 10:27 (NonPanicPathOnly), mp5@src/main.rs:10:9: 10:27 (Deep), mp4@src/main.rs:10:9: 10:27 (NonPanicPathOnly), mp3@src/main.rs:10:9: 10:27 (Deep), mp2@src/main.rs:10:9: 10:36 (NonPanicPathOnly), mp11@src/main.rs:11:9: 11:14 (Deep), mp10@src/main.rs:11:9: 11:14 (Deep), mp0@src/main.rs:9:16: 12:6 (Deep)], init_loc_map: LocationMap { map: [[[], [], [], [], [], [], [], [in1], [in2]], [[in3], [], [in4]], [[]], [[]], [[in5], [in6]], [[in7], [], [], [in8]], [[]], [[]], [[]], [[]], [[], [], []], [[], [], [], [in9], []], [[in10], [], [in11], []], [[]], [[]], [[]]] }, init_path_map: [[in11], [in0], [in8], [in7], [in6], [in5], [in4], [in3], [in2], [in1], [in10], [in9]] }, [IllegalMove { cannot_move_out_of: IllegalMoveOrigin { span: src/main.rs:10:9: 10:27, kind: BorrowedContent } }])', libcore/result.rs:916:5
stack backtrace:
   0:        0x109f23bab - std::sys::unix::backtrace::tracing::imp::unwind_backtrace::hb00ae1fbed16a78a
   1:        0x109f2f89e - std::sys_common::backtrace::print::hf36ed66abb5dec36
   2:        0x109f11e50 - std::panicking::default_hook::{{closure}}::ha90d4c866bd13547
   3:        0x109f11935 - std::panicking::default_hook::hfd2d1b85accf952b
   4:        0x109f122d6 - std::panicking::rust_panic_with_hook::hca4836ceadb52bda
   5:        0x109f121ae - std::panicking::begin_panic::hc0cdca14ab0bf4ba
   6:        0x109f12083 - std::panicking::begin_panic_fmt::hb46649ba52f55429
   7:        0x109f11ff2 - rust_begin_unwind
   8:        0x109f9c243 - core::panicking::panic_fmt::h5760b74cba8293a5
   9:        0x107d3780d - core::result::unwrap_failed::h6a1acabdff3d0eec
  10:        0x107d0f13e - <rustc_mir::transform::elaborate_drops::ElaborateDrops as rustc_mir::transform::MirPass>::run_pass::h747dc48ca9895755
  11:        0x107c9ed1b - rustc_mir::transform::optimized_mir::{{closure}}::hfa2c280020d3ce13
  12:        0x107c9d480 - rustc_mir::transform::optimized_mir::ha00b500d245fc403
  13:        0x10869e3cb - rustc::ty::maps::<impl rustc::ty::maps::queries::optimized_mir<'tcx>>::compute_result::hdc4a263a98158641
  14:        0x10877ae44 - rustc::dep_graph::graph::DepGraph::with_task_impl::h68143cbe1a9f97d5
  15:        0x10840c2a9 - rustc_errors::Handler::track_diagnostics::h50bfc12ff579da45
  16:        0x1089038a0 - rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::cycle_check::h34d534ce00b6fcf7
  17:        0x10869e457 - rustc::ty::maps::<impl rustc::ty::maps::queries::optimized_mir<'tcx>>::force::hbda1b1132bda3f85
  18:        0x10869ebcb - rustc::ty::maps::<impl rustc::ty::maps::queries::optimized_mir<'tcx>>::try_get::h9cf3822b490e0f01
  19:        0x1087f8080 - rustc::ty::maps::TyCtxtAt::optimized_mir::haae9d93689f8eefc
  20:        0x108846fa3 - rustc::ty::sty::ClosureSubsts::field_tys::h8fd7b2516bb1163a
  21:        0x107db489a - rustc_mir::borrow_check::nll::type_check::TypeChecker::typeck_mir::hd7ac2903ec768b89
  22:        0x107daabcd - rustc_mir::borrow_check::nll::type_check::type_check_internal::h6c3133caba4342ea
  23:        0x107cae37f - rustc::ty::context::tls::enter::h70f5fa31abd1ad21
  24:        0x107d68e3f - rustc::infer::InferCtxtBuilder::enter::h4680b6a4bf730a54
  25:        0x107db77a2 - <rustc_mir::borrow_check::nll::type_check::TypeckMir as rustc_mir::transform::MirPass>::run_pass::h4fd610f0b6b66e61
  26:        0x107c9e249 - rustc_mir::transform::mir_const::{{closure}}::hc40a872c7350d68c
  27:        0x107c9d078 - rustc_mir::transform::mir_const::h0351d4971ca6ebdf
  28:        0x10869b90b - rustc::ty::maps::<impl rustc::ty::maps::queries::mir_const<'tcx>>::compute_result::hb8a281daa66135cd
  29:        0x108775e24 - rustc::dep_graph::graph::DepGraph::with_task_impl::h48d605fbff117d9a
  30:        0x108406809 - rustc_errors::Handler::track_diagnostics::h32ef0a507c5dd5df
  31:        0x108931e70 - rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::cycle_check::hb1bac88a62839f0b
  32:        0x10869b997 - rustc::ty::maps::<impl rustc::ty::maps::queries::mir_const<'tcx>>::force::hee54d72e3401bac7
  33:        0x10869c100 - rustc::ty::maps::<impl rustc::ty::maps::queries::mir_const<'tcx>>::try_get::he171ddd9fe88fdac
  34:        0x1087f7ea0 - rustc::ty::maps::TyCtxtAt::mir_const::hab99d6c9e77dfbf4
  35:        0x108959f43 - rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::mir_const::hf9e51693a91842c6
  36:        0x107c9d252 - rustc_mir::transform::mir_validated::h13c0973e82916778
  37:        0x10869ce6b - rustc::ty::maps::<impl rustc::ty::maps::queries::mir_validated<'tcx>>::compute_result::hee6bdf13a75fe72c
  38:        0x108775e24 - rustc::dep_graph::graph::DepGraph::with_task_impl::h48d605fbff117d9a
  39:        0x108418969 - rustc_errors::Handler::track_diagnostics::h8861c27316edbd88
  40:        0x108941e50 - rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::cycle_check::he132784372d189f4
  41:        0x10869cef7 - rustc::ty::maps::<impl rustc::ty::maps::queries::mir_validated<'tcx>>::force::hfbf3a4807f19d884
  42:        0x10869d660 - rustc::ty::maps::<impl rustc::ty::maps::queries::mir_validated<'tcx>>::try_get::hd6aaf4e01bb964da
  43:        0x1087f7f90 - rustc::ty::maps::TyCtxtAt::mir_validated::h23f34482bc52bd78
  44:        0x108959f73 - rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::mir_validated::hf3587735b5a14d04
  45:        0x107b8026b - rustc_borrowck::borrowck::borrowck::h11e8ba64c24145d9
  46:        0x10877b7a2 - rustc::dep_graph::graph::DepGraph::with_task_impl::h6834951daf031258
  47:        0x1084208b9 - rustc_errors::Handler::track_diagnostics::ha885c61e4d186bff
  48:        0x1089198a0 - rustc::ty::maps::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::cycle_check::h6e59ac1032587978
  49:        0x1086ac557 - rustc::ty::maps::<impl rustc::ty::maps::queries::borrowck<'tcx>>::force::hf280f025ebc910a1
  50:        0x1086acc55 - rustc::ty::maps::<impl rustc::ty::maps::queries::borrowck<'tcx>>::try_get::h3087dea5e2e013ca
  51:        0x1087f89e2 - rustc::ty::maps::TyCtxtAt::borrowck::h06c2cbc0702f5c60
  52:        0x10895a1b3 - rustc::ty::maps::<impl rustc::ty::context::TyCtxt<'a, 'tcx, 'lcx>>::borrowck::h232ca7089166992d
  53:        0x107b7ffe1 - rustc_borrowck::borrowck::check_crate::h72c5192c8cad1ef1
  54:        0x103ba8921 - <std::thread::local::LocalKey<T>>::with::h4ceb21c51d383228
  55:        0x103ba909c - <std::thread::local::LocalKey<T>>::with::h523066c0aa34625d
  56:        0x103c0940d - rustc::ty::context::TyCtxt::create_and_enter::h9fc0e01596742138
  57:        0x103bd4e80 - rustc_driver::driver::compile_input::h79f5a6577555cf39
  58:        0x103bdcf0e - rustc_driver::run_compiler::h451b54d7493e8f3b
  59:        0x103b047c1 - std::sys_common::backtrace::__rust_begin_short_backtrace::h6ce56a7d644f541f
  60:        0x109f5611e - __rust_maybe_catch_panic
  61:        0x103b49d4d - <F as alloc::boxed::FnBox<A>>::call_box::h727cb74d478d9b7e
  62:        0x109f32237 - std::sys_common::thread::start_thread::h6da1675f0959472c
  63:        0x109f3c0f8 - std::sys::unix::thread::Thread::new::thread_start::habc04e704e134061
  64:     0x7fff9601293a - _pthread_body
  65:     0x7fff96012886 - _pthread_start