rustc ICE on Pippin

gistfile1.txt

dhardy@localhost:~/other/pippin$ cargo clean
dhardy@localhost:~/other/pippin$ cargo build
   Compiling num-traits v0.1.32
   Compiling log v0.3.6
   Compiling byteorder v0.5.1
   Compiling regex-syntax v0.3.1
   Compiling gcc v0.3.27
   Compiling winapi-build v0.1.1
   Compiling vec_map v0.6.0
   Compiling hashindexed v0.1.0
   Compiling libc v0.2.10
   Compiling libc v0.1.12
   Compiling void v1.0.2
   Compiling winapi v0.2.6
   Compiling unreachable v0.1.1
   Compiling rustc-serialize v0.3.19
   Compiling utf8-ranges v0.1.3
   Compiling kernel32-sys v0.2.2
   Compiling rust-crypto v0.2.35
   Compiling walkdir v0.1.5
   Compiling memchr v0.1.11
   Compiling time v0.1.35
   Compiling rand v0.3.14
   Compiling aho-corasick v0.5.1
   Compiling thread-id v2.0.0
   Compiling thread_local v0.2.3
   Compiling num-integer v0.1.32
   Compiling num-iter v0.1.32
   Compiling num v0.1.32
   Compiling chrono v0.2.21
   Compiling regex v0.1.66
   Compiling pippin v0.0.0 (file:///home/dhardy/other/pippin)
dhardy@localhost:~/other/pippin$ cargo test
   Compiling strsim v0.3.0
   Compiling env_logger v0.3.3
   Compiling docopt v0.6.80
   Compiling pippin v0.0.0 (file:///home/dhardy/other/pippin)
examples/pippincmd.rs:6:12: 6:20 warning: unused or unknown feature, #[warn(unused_features)] on by default
examples/pippincmd.rs:6 #![feature(str_char)]
                                   ^~~~~~~~
error: internal compiler error: ../src/librustc/infer/mod.rs:564: Encountered errors `[FulfillmentError(Obligation(predicate=Binder(ProjectionPredicate(ProjectionTy { trait_ref: <SeqClassifier as pippin::ClassifierT>, item_name: Element(153) }, <SeqClassifier as pippin::ClassifierT>::Element)),depth=2),MismatchedProjectionTypes(Sorts(ExpectedFound { expected: Sequence, found: <SeqClassifier as pippin::ClassifierT>::Element })))]` fulfilling during trans
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<Any>', ../src/libsyntax/errors/mod.rs:537
stack backtrace:
   1:     0x7fa2b0fed610 - std::sys::backtrace::tracing::imp::write::h9fb600083204ae7f
   2:     0x7fa2b0ffad5b - std::panicking::default_hook::_$u7b$$u7b$closure$u7d$$u7d$::hca543c34f11229ac
   3:     0x7fa2b0ffa8fc - std::panicking::default_hook::hc2c969e7453d080c
   4:     0x7fa2b0fc028f - std::sys_common::unwind::begin_unwind_inner::h30e12d15ce2b2e25
   5:     0x7fa2afaa2ea8 - std::sys_common::unwind::begin_unwind::h24c4c0fa2cfe995a
   6:     0x7fa2afaa2e4b - syntax::errors::Handler::span_bug::h1878d6587b8bfd95
   7:     0x7fa2afad7ac2 - rustc::session::opt_span_bug_fmt::_$u7b$$u7b$closure$u7d$$u7d$::hf0fb5697f8f25f40
   8:     0x7fa2afad79b2 - rustc::session::span_bug_fmt::h4591bcbadfc38558
   9:     0x7fa2afaec04c - rustc_trans::common::fulfill_obligation::hb97500cd4d49823c
  10:     0x7fa2afae4a99 - rustc_trans::callee::Callee::def::ha169529fef0048b5
  11:     0x7fa2afbe611e - _<std..option..Option<T>>::map::h54e7f9a0f99f0360
  12:     0x7fa2afbe5d53 - _<std..vec..Vec<T> as std..iter..FromIterator<T>>::from_iter::he173b9fb2f4cc1c2
  13:     0x7fa2afbe57c3 - rustc_trans::meth::get_vtable::_$u7b$$u7b$closure$u7d$$u7d$::hd7ec4b80d346f375
  14:     0x7fa2afbe6942 - _<std..iter..FlatMap<I, U, F> as std..iter..Iterator>::next::ha090509351b98638
  15:     0x7fa2afbe6b83 - _<std..vec..Vec<T>>::extend_desugared::hfc30acdd7688509c
  16:     0x7fa2afbe6609 - core::iter::iterator::Iterator::collect::h42fa202d3651b5e6
  17:     0x7fa2afae6822 - rustc_trans::base::unsized_info::hd31be9e24e239b50
  18:     0x7fa2afbaba66 - rustc_trans::expr::coerce_unsized::h6fa5deecc673f1b4
  19:     0x7fa2afb55860 - rustc_trans::expr::trans::h4425e9280a87b757
  20:     0x7fa2afb5312e - rustc_trans::callee::trans_args::h9cc59c5a5b26cbc0
  21:     0x7fa2afae3ec6 - rustc_trans::callee::Callee::call::h54d29fdb586ad3c4
  22:     0x7fa2afba88b3 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  23:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  24:     0x7fa2afb8824b - rustc_trans::controlflow::trans_stmt_semi::h1cfba097d89a5175
  25:     0x7fa2afb03ea0 - rustc_trans::controlflow::trans_block::h4fad28c271095568
  26:     0x7fa2afba6ee2 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  27:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  28:     0x7fa2afbd953e - rustc_trans::_match::trans_match_inner::hb81fe2e930f621a8
  29:     0x7fa2afba6053 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  30:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  31:     0x7fa2afb041cd - rustc_trans::controlflow::trans_block::h4fad28c271095568
  32:     0x7fa2afba9b2c - rustc_trans::expr::trans_rvalue_stmt_unadjusted::hce285cdde393b03d
  33:     0x7fa2afb0c658 - rustc_trans::expr::trans_into::he1315719b2222c7c
  34:     0x7fa2afbd953e - rustc_trans::_match::trans_match_inner::hb81fe2e930f621a8
  35:     0x7fa2afba6053 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  36:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  37:     0x7fa2afbe4dcd - rustc_trans::_match::mk_binding_alloca::h10ee057521a27e54
  38:     0x7fa2afaefc6d - rustc_trans::base::init_local::hcde0b67ec7b31973
  39:     0x7fa2afb03ec4 - rustc_trans::controlflow::trans_block::h4fad28c271095568
  40:     0x7fa2afba6ee2 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  41:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  42:     0x7fa2afb8824b - rustc_trans::controlflow::trans_stmt_semi::h1cfba097d89a5175
  43:     0x7fa2afb03ea0 - rustc_trans::controlflow::trans_block::h4fad28c271095568
  44:     0x7fa2afba6ee2 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  45:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  46:     0x7fa2afbd953e - rustc_trans::_match::trans_match_inner::hb81fe2e930f621a8
  47:     0x7fa2afba6053 - rustc_trans::expr::trans_rvalue_dps_unadjusted::h4d8aac465b9b8fed
  48:     0x7fa2afb0c67d - rustc_trans::expr::trans_into::he1315719b2222c7c
  49:     0x7fa2afb8824b - rustc_trans::controlflow::trans_stmt_semi::h1cfba097d89a5175
  50:     0x7fa2afb03ea0 - rustc_trans::controlflow::trans_block::h4fad28c271095568
  51:     0x7fa2afb02c85 - rustc_trans::base::trans_closure::h83a389352ac0be25
  52:     0x7fa2afb048f3 - rustc_trans::base::trans_fn::h9423938066432dd9
  53:     0x7fa2afb0ee91 - rustc_trans::base::trans_item::hdc785ae68a9e6500
  54:     0x7fa2afb28ecb - _<base..TransItemsWithinModVisitor<'a, 'tcx> as rustc..hir..intravisit..Visitor<'v>>::visit_item::h22c1c36dec64effa
  55:     0x7fa2afb177cb - rustc_trans::base::trans_crate::h6ed1dbd6e572a8c2
  56:     0x7fa2b15526ff - rustc_driver::driver::phase_4_translate_to_llvm::hd7579aae98641824
  57:     0x7fa2b1550d8f - rustc_driver::driver::compile_input::_$u7b$$u7b$closure$u7d$$u7d$::he3c6b6ab9afe28dd
  58:     0x7fa2b154d630 - rustc_driver::driver::phase_3_run_analysis_passes::_$u7b$$u7b$closure$u7d$$u7d$::h06c776ef4d1c70b6
  59:     0x7fa2b1546f5e - rustc::ty::context::TyCtxt::create_and_enter::hb0e0e916c7274a64
  60:     0x7fa2b151990d - rustc_driver::driver::compile_input::h0629572e6f316b31
  61:     0x7fa2b14fa53c - rustc_driver::run_compiler::h8902aebf8b1849a8
  62:     0x7fa2b14f7c41 - std::sys_common::unwind::try::try_fn::h4c74456035d0fcc7
  63:     0x7fa2b0feadeb - __rust_try
  64:     0x7fa2b0fead7d - std::sys_common::unwind::inner_try::h47a4d9cd4a369dcd
  65:     0x7fa2b14f848a - _<F as std..boxed..FnBox<A>>::call_box::h27f542a39f1d61ef
  66:     0x7fa2b0ff8ef4 - std::sys::thread::Thread::new::thread_start::h6f266e069bf4ec2b
  67:     0x7fa2a8d60609 - start_thread
  68:     0x7fa2b0c52a4c - clone
  69:                0x0 - <unknown>

Build failed, waiting for other jobs to finish...
error: Could not compile `pippin`.

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