ICE in parser with malformed extern decl

[brson]

fn main() {
}

extern {
    what();
}

rust: task failed at 'assertion failed: *self.token == token::RBRACE', /home/brian/dev/rust/src/libsyntax/parse/parser.rs:3711
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,::rt::backtrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/brian/dev/rust/src/librustc/rustc.rc:350
rust: domain main @0x2033410 root task failed