Compiler crash when matching on extern static constant

[senbrow]

The following code results in a compiler crash on rustc 0.12.0-pre-nightly (5ebf4813a 2014-07-29 21:16:50 +0000)

extern {
    static externalValue: int;
}

fn main() {
    let boolValue = match 42 {
        externalValue => true,
        _ => false
    };
}

Here is a stack trace:

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 'called `Option::unwrap()` on a `None` value', /Users/rustbuild/src/rust-buildbot/slave/nightly-mac/build/src/libcore/option.rs:270

stack backtrace:
   1:        0x105f65755 - rt::backtrace::imp::write::hbb253ba4ead9d701Ojq
   2:        0x105f69005 - failure::on_fail::hae29c97c183bf809jAq
   3:        0x10621c125 - unwind::begin_unwind_inner::heb1c638fe2cfececKUd
   4:        0x10621bcfb - unwind::begin_unwind_fmt::he787b6ed8668ca88cSd
   5:        0x10621bb52 - rust_begin_unwind
   6:        0x10626b6ac - failure::begin_unwind::hd9f539f711819e41HZj
   7:        0x102f394c9 - middle::check_match::StaticInliner<'a>.Folder::fold_pat::h474c6bec3dfe65a7Efm
   8:        0x102f34b4b - middle::check_match::check_expr::h6c2a28fd45487372Y0l
   9:        0x102f361fc - middle::check_match::check_local::h7a2b12847be50b08w6m
  10:        0x102f38b1c - visit::walk_block::h11178504046137318959
  11:        0x102f3685c - middle::check_match::check_fn::hfc000f70b7e57dbb08m
  12:        0x102f37863 - visit::walk_item::h18258468695370448187
  13:        0x102f36d5c - middle::check_match::check_crate::ha408d2752ab3565bu0l
  14:        0x102cfeaaa - util::common::time::h11760416629416974346
  15:        0x103562777 - driver::driver::phase_3_run_analysis_passes::h04c7a7a5096a3f33sUv
  16:        0x10355cdb0 - driver::driver::compile_input::h025bdd4f61abfaebHGv
  17:        0x103604f27 - driver::run_compiler::h67f285fbf1017e5aiLy
  18:        0x1036036d6 - driver::main_args::closure.$x22closure$x22$LP$134662$RP$
  19:        0x10361535b - task::TaskBuilder<S>::try_future::closure.$x22closure$x22$LP$135806$RP$
  20:        0x103615250 - task::TaskBuilder<S>::spawn_internal::closure.$x22closure$x22$LP$135783$RP$
  21:        0x105e9974c - task::spawn_opts::closure.$x22closure$x22$LP$8296$RP$
  22:        0x10628162c - rust_try
  23:        0x1062193fb - unwind::try::h96e922d0c8f226806Id
  24:        0x1062191a3 - task::Task::run::he3c21bcb4266b9cbyRc
  25:        0x105e995e1 - task::spawn_opts::closure.$x22closure$x22$LP$8241$RP$
  26:        0x10621b076 - thread::thread_start::h585497a1f88d9975ofd
  27:     0x7fff84e38899 - _pthread_body
  28:     0x7fff84e3872a - _pthread_struct_init

This is on OSX 10.9.4. Here is the output of uname -a

$ uname -a
Darwin slimjim 13.3.0 Darwin Kernel Version 13.3.0: Tue Jun  3 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64 i386 MacBookPro11,3 Darwin

[ghost]

These should probably not be allowed at all as in other contexts extern statics are not considered constant (say, SIZE in [T, ..SIZE]).