backtrace.txt

stack backtrace:
	   1:        0x10e472c45 - rt::backtrace::imp::write::hd2f888e449bbd94eoiq
	   2:        0x10e475dc3 - failure::on_fail::he27adfa3d8f252c2Tyq
	   3:        0x10e47ceb5 - unwind::begin_unwind_inner::h5b97974f8716d208S5d
	   4:        0x10e47ca8b - unwind::begin_unwind_fmt::hc263c2d677566b22n3d
	   5:        0x10e47c8e2 - rust_begin_unwind
	   6:        0x10e49e62c - failure::begin_unwind::h4e97151c53e68d96j5j
	   7:        0x10e2bd0fc - option::Option<T>::unwrap::h2778475912063396917
	   8:        0x10e2bcf09 - json::Decoder::pop::hab5b5f6e228e32aftQd
	   9:        0x10e31f5c7 - json::Decoder...Decoder<DecoderError>::read_struct::h14270248516275819116
	  10:        0x10e31f229 - json::tests::test_missing_field::Foo.Decodable<D, E>::decode::h1046967682188618469
	  11:        0x10e31eb51 - json::tests::test_missing_field::h8c0be0ef7324a34ccjm
	  12:        0x10e3ea5ab - task::TaskBuilder<S>::try_future::closure.8296
	  13:        0x10e3ea4b5 - task::TaskBuilder<S>::spawn_internal::closure.8273
	  14:        0x10e3b874c - task::spawn_opts::closure.8415
	  15:        0x10e47db6c - rust_try_inner
	  16:        0x10e47db56 - rust_try
	  17:        0x10e47abab - unwind::try::h6aa608f8f9f9fc27nUd
	  18:        0x10e47a98b - task::Task::run::hccbff863f07b263bv2c
	  19:        0x10e3b85aa - task::spawn_opts::closure.8360
	  20:        0x10e47bf76 - thread::thread_start::hc4dd42436eada49fFqd
	  21:     0x7fff8cfba657 - _pthread_body
	  22:     0x7fff8cfba5d4 - _pthread_body

task 'json::tests::test_missing_field' failed at 'called Option::unwrap() on a None value', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libcore/option.rs:262