Description
I encountered this error while building "router" crate.
/Users/.cargo/registry/src/github.com-1ecc6299db9ec823/router-0.0.9/src/router.rs:158:1: 158:45 error: internal compiler error: coherence failed to report ambiguity: cannot locate the impl of the trait core::marker::MarkerTrait for the type iron::middleware::Handler
/Users/biye/.cargo/registry/src/github.com-1ecc6299db9ec823/router-0.0.9/src/router.rs:158 impl Key for Router { type Value = Params; }
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with RUST_BACKTRACE=1 for a backtrace
thread 'rustc' panicked at 'Box', /Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/src/libsyntax/diagnostic.rs:130
stack backtrace:
1: 0x1090eddf7 - sys::backtrace::write::hcdd8cf990b8f0f0e1LC
2: 0x10911bccd - panicking::on_panic::hbbf8c269bccad920HAI
3: 0x10904015e - rt::unwind::begin_unwind_inner::h2f66a36e4dcc3e43iiI
4: 0x1088174ee - rt::unwind::begin_unwind::h4366604798127356786
5: 0x10881749b - diagnostic::SpanHandler::span_bug::h0e21e2a54cd366dbjnB
6: 0x1062d2666 - middle::traits::error_reporting::report_fulfillment_error::h24e2f9dcf11073a7hTN
7: 0x10613ede1 - middle::traits::error_reporting::report_fulfillment_errors::he23632a94223023axSN
8: 0x10567f7c2 - check::vtable::select_all_fcx_obligations_or_error::hded438f3b654ae6bX1b
9: 0x10570b76e - check::wf::CheckTypeWellFormedVisitor<'ccx, 'tcx>::check_item_well_formed::h50d40da11e7554f3mWk
10: 0x105714261 - visit::walk_item::h17483634980229280695
11: 0x105814569 - check_crate::closure.36302
12: 0x10580ea37 - check_crate::hf2047274e19fe4f4bwC
13: 0x10552c2d5 - driver::phase_3_run_analysis_passes::h7ac32f1d1ca0be7dgGa
14: 0x105510a05 - driver::compile_input::haed712778d66caf6Qba
15: 0x1055ce985 - run_compiler::h2df8296b9f7c362fV4b
16: 0x1055cc152 - boxed::F.FnBox::call_box::h8968837061369711197
17: 0x1055cb647 - rt::unwind::try::try_fn::h5695919628988619761
18: 0x1091a5d28 - rust_try_inner
19: 0x1091a5d15 - rust_try
20: 0x1055cb93a - boxed::F.FnBox::call_box::h17367168855684310088
21: 0x1091051fd - sys::thread::create::thread_start::he0d7c708bf73803bihH
22: 0x7fff8c0a2267 - _pthread_body
23: 0x7fff8c0a21e4 - _pthread_start