Even non reexported ones, e.g. http://doc.rust-lang.org/nightly/core/ops/trait.FnOnce.html#tymethod.call_once is really `extern "rust-call" fn call_once`.
Even non reexported ones, e.g. http://doc.rust-lang.org/nightly/core/ops/trait.FnOnce.html#tymethod.call_once is really
extern "rust-call" fn call_once.