error

make rlib
clear \
	&& rustc --target "x86_64-apple-darwin" -O --crate-type=rlib src/lib.rs -L "target/x86_64-apple-darwin/lib" --out-dir "target/x86_64-apple-darwin/lib/" \
	&& clear \
	&& echo "--- Built rlib" \
	&& echo "--- Type 'make test' to test library"
task 'rustc' failed at 'index out of bounds: the len is 0 but the index is 0', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/librustc/lib.rs:1
stack backtrace:
   1:        0x10cf55844 - rt::backtrace::imp::write::h254d0a6dd1fae24biCa::v0.11.pre
   2:        0x10ceb78de - rt::unwind::begin_unwind_inner::h6e474448729455a4oca::v0.11.pre
   3:        0x10ceb7068 - rt::unwind::begin_unwind::h7603572080577830236::v0.11.pre
   4:        0x10cf55309 - rt::unwind::begin_unwind_raw::h0893674862f52c69x99::v0.11.pre
   5:        0x10ceb62de - rt::unwind::fail_::h986c56d6444ce004b79::v0.11.pre
   6:        0x10cf55352 - rt::unwind::fail_bounds_check::closure.40229
   7:        0x10ceb83ee - rt::unwind::fail_bounds_check::haa7cd8c92bfd2426y79::v0.11.pre
   8:        0x10a63ad43 - middle::lint::Context<'a>.Visitor<(*>::visit_pat::h3f890388c8349bd1QAC::v0.11.pre
   9:        0x10a64137f - visit::walk_fn::h14159244373675001984::v0.11.pre
  10:        0x10a641300 - middle::lint::Context<'a>.Visitor<(*>::visit_fn::closure.70856
  11:        0x10a64178e - middle::lint::Context<'a>.Visitor<(*>::visit_fn::closure.70858
  12:        0x10a621081 - middle::lint::Context<'a>::with_lint_attrs::hc3354270c7d80aad1jB::v0.11.pre
  13:        0x10a639e20 - middle::lint::Context<'a>.Visitor<(*>::visit_fn::h47a5ba7dfb59a1d2IDC::v0.11.pre
  14:        0x10a6331db - middle::lint::Context<'a>.Visitor<(*>::visit_item::closure.70842
  15:        0x10a621081 - middle::lint::Context<'a>::with_lint_attrs::hc3354270c7d80aad1jB::v0.11.pre
  16:        0x10a639fd6 - visit::Visitor::visit_mod::h5439476737720994357::v0.11.pre
  17:        0x10a647dc7 - middle::lint::check_crate::closure.70913
  18:        0x10a621081 - middle::lint::Context<'a>::with_lint_attrs::hc3354270c7d80aad1jB::v0.11.pre
  19:        0x10a647415 - middle::lint::check_crate::h89f594bd5ee870c60JC::v0.11.pre
  20:        0x10a5f379f - util::common::time::h14699901310049870540::v0.11.pre
  21:        0x10aa0fca1 - driver::driver::phase_3_run_analysis_passes::h8e28097da6e59f487Df::v0.11.pre
  22:        0x10aa14f62 - driver::driver::compile_input::h5c1c854541bd3a7eU3f::v0.11.pre
  23:        0x10aa3add2 - run_compiler::h62e9fe55eaa01b0dLAn::v0.11.pre
  24:        0x10aa4ec4d - main_args::closure.91516
  25:        0x10aa4cfe2 - monitor::closure.91391
  26:        0x10aa48b2b - task::TaskBuilder::try::closure.91157
  27:        0x10cba247c - task::spawn_opts::closure.7105
  28:        0x10cf50948 - rt::task::Task::run::closure.40126
  29:        0x10cf5a6bc - rust_try
  30:        0x10cf507c7 - rt::task::Task::run::h67dcf35100df5a07Y27::v0.11.pre
  31:        0x10cba22ff - task::spawn_opts::closure.7077
  32:        0x10cf54216 - rt::thread::thread_start::he31c712e1f859f82bI8::v0.11.pre
  33:     0x7fff92256899 - _pthread_body
  34:     0x7fff9225672a - _pthread_struct_init

gistfile1.rs

pub enum Key {
    LeftKey
}

pub trait Game {
    fn key_press(&mut self, Key) {}
}

Notice that Key is invalid syntax.