#![feature(box_patterns)]
#![feature(box_syntax)]
-#![feature(const_fn)]
#![feature(custom_attribute)]
#![allow(unused_attributes)]
#![feature(i128_type)]
#![feature(slice_patterns)]
#![feature(conservative_impl_trait)]
+#![cfg_attr(stage0, feature(const_fn))]
+#![cfg_attr(not(stage0), feature(const_atomic_bool_new))]
+#![cfg_attr(not(stage0), feature(const_once_new))]
+
use rustc::dep_graph::WorkProduct;
use syntax_pos::symbol::Symbol;