#![feature(core_intrinsics)]
#![feature(discriminant_kind)]
#![feature(exhaustive_patterns)]
+#![feature(generators)]
#![feature(get_mut_unchecked)]
#![feature(if_let_guard)]
+#![feature(iter_from_generator)]
#![feature(negative_impls)]
#![feature(never_type)]
#![feature(extern_types)]