ICE: Using fn when proc is expected

[TyOverby]

Using rustc 0.12.0-pre-nightly (4dfdc697e 2014-08-21 00:51:00 +0000) with cargo-nightly 0.1.0-pre (3e5ba33 2014-07-29 00:14:32 +0000).

When attempting to test this project
by running cargo test the compiler crashes with:

   Compiling assert_that v0.0.0-alpha (file:/home/ty/workspace/rust/assert_that)
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
task 'rustc' failed at 'assertion failed: `(left == right) && (right == left)` (left: `many`, right: `once`)', /home/rustbuild/src/rust-buil
dbot/slave/nightly-linux/build/src/librustc/util/ppaux.rs:301

stack backtrace:
   1:     0x7f229e711ca0 - rt::backtrace::imp::write::hcfbe43e70bb1e32bpxr
   2:     0x7f229e714d70 - failure::on_fail::h3a83fc31a26616e26Sr
   3:     0x7f22a2d56cc0 - unwind::begin_unwind_inner::h5e11d7c7f0cfb20dpie
   4:     0x7f22a2d569b0 - unwind::begin_unwind_fmt::h5cfb3c3393b45e1fPfe
   5:     0x7f22a33bb440 - util::ppaux::ty_to_string::h793dcd4c5e43f8c0mtI
   6:     0x7f22a33baf40 - back::link::mangle_internal_name_by_type_and_seq::h2b4f82d8f7fbfc69clb
   7:     0x7f22a37b9720 - middle::trans::glue::declare_generic_glue::h621052a8516a9017m5Z
   8:     0x7f22a37b8920 - middle::trans::glue::get_drop_glue::h74866def10d5fddawvZ
   9:     0x7f22a37b8800 - middle::trans::glue::drop_ty::hb7c2867d4f693fbbatZ
  10:     0x7f22a38dac60 - middle::trans::cleanup::DropValue.Cleanup::trans::h61040af50c3bee0driy
  11:     0x7f22a38d8260 - middle::trans::cleanup::FunctionContext<'a>.CleanupHelperMethods<'a>::trans_cleanups_to_exit_scope::h08b80b8f63dd
4794PNx
  12:     0x7f22a38dc450 - middle::trans::cleanup::FunctionContext<'a>.CleanupHelperMethods<'a>::get_or_create_landing_pad::h24c2228799a9273
3F4x
  13:     0x7f22a384ae50 - middle::trans::cleanup::FunctionContext<'a>.CleanupMethods<'a>::get_landing_pad::h54f32dbd3b5d84ffAzx
  14:     0x7f22a37bf820 - middle::trans::base::invoke::h209f860a0c738ae5Lkd
  15:     0x7f22a37abc00 - middle::trans::callee::trans_call_inner::h059b07b43ceb0880nR1
  16:     0x7f22a37d6040 - middle::trans::callee::trans_method_call::h245b5473d346fef3BM1
  17:     0x7f22a37e3df0 - middle::trans::expr::trans_rvalue_dps_unadjusted::hc6db395c8ae555feuG3
  18:     0x7f22a37e3000 - middle::trans::expr::trans_unadjusted::h8783e4940f88def2l92
  19:     0x7f22a37a3b00 - middle::trans::expr::trans::ha89c9e4ea08f3635MP2
  20:     0x7f22a37a2200 - middle::trans::expr::trans_to_lvalue::hd8de036436e7b9f4n82
  21:     0x7f22a37ee890 - middle::trans::expr::trans_addr_of::hf52d57f69815379cly4
  22:     0x7f22a37e3000 - middle::trans::expr::trans_unadjusted::h8783e4940f88def2l92
  23:     0x7f22a37a3b00 - middle::trans::expr::trans::ha89c9e4ea08f3635MP2
  24:     0x7f22a37db610 - middle::trans::callee::trans_args::h467443c32fd8eaa9qi2
  25:     0x7f22a37abc00 - middle::trans::callee::trans_call_inner::h059b07b43ceb0880nR1
  26:     0x7f22a37d5430 - middle::trans::callee::trans_call::ha54eafed13f71ea3sL1
  27:     0x7f22a37e3df0 - middle::trans::expr::trans_rvalue_dps_unadjusted::hc6db395c8ae555feuG3
  28:     0x7f22a37a2340 - middle::trans::expr::trans_into::h4cc7d5c86b574b12QL2
  29:     0x7f22a37a17b0 - middle::trans::controlflow::trans_stmt_semi::hafd0c306b0e45dfeeMY
  30:     0x7f22a37a0ee0 - middle::trans::controlflow::trans_stmt::h1a4d7b374816b79fXHY
  31:     0x7f22a37a28d0 - middle::trans::controlflow::trans_block::hc815caf3f5bd13398MY
  32:     0x7f22a3853ea0 - middle::trans::base::trans_closure::h1991c9bfd6853f43Zve
  33:     0x7f22a37936e0 - middle::trans::base::trans_fn::h3a05e8d9cb39f052NIe
  34:     0x7f22a378ec20 - middle::trans::base::trans_item::h7355b51ee1fa63f9O1e
  35:     0x7f22a378ec20 - middle::trans::base::trans_item::h7355b51ee1fa63f9O1e
  36:     0x7f22a378ec20 - middle::trans::base::trans_item::h7355b51ee1fa63f9O1e
  37:     0x7f22a385ffc0 - middle::trans::base::trans_crate::ha7c47b047d4256a32Wf
  38:     0x7f22a3c7ea40 - driver::driver::phase_4_translate_to_llvm::hc918e565e0c85a6az0z
  39:     0x7f22a3c75cc0 - driver::driver::compile_input::hd5f78bd4a274d8f20Cz
  40:     0x7f22a3d24200 - driver::run_compiler::h406aa3244f78df8cUaD
  41:     0x7f22a3d24110 - driver::main_args::closure.137674
  42:     0x7f22a3d36b40 - task::TaskBuilder<S>::try_future::closure.138835
  43:     0x7f22a3d36940 - task::TaskBuilder<S>::spawn_internal::closure.138812
  44:     0x7f22a30bab10 - task::spawn_opts::closure.8332
  45:     0x7f22a2db0150 - rust_try_inner
  46:     0x7f22a2db0140 - rust_try
  47:     0x7f22a2d54320 - unwind::try::h712e7b6e53c5d278F6d
  48:     0x7f22a2d540c0 - task::Task::run::h149056d48d246899Zcd
  49:     0x7f22a30ba8d0 - task::spawn_opts::closure.8278
  50:     0x7f22a2d55f00 - thread::thread_start::h996a50155a983571LBd
  51:     0x7f229da830c0 - start_thread
  52:     0x7f22a2a1f2d9 - __clone
  53:                0x0 - <unknown>

Could not compile `assert_that`.

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