diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs
index aaac7fb4460c..13792a0c890c 100644
--- a/src/librustc_data_structures/lib.rs
+++ b/src/librustc_data_structures/lib.rs
@@ -12,7 +12,6 @@
 #![feature(generators)]
 #![feature(generator_trait)]
 #![feature(fn_traits)]
-#![feature(unsize)]
 #![feature(specialization)]
 #![feature(optin_builtin_traits)]
 #![feature(nll)]
@@ -20,11 +19,9 @@
 #![feature(hash_raw_entry)]
 #![feature(stmt_expr_attributes)]
 #![feature(core_intrinsics)]
-#![feature(integer_atomics)]
 #![feature(test)]
 #![feature(associated_type_bounds)]
 #![feature(thread_id_value)]
-#![cfg_attr(unix, feature(libc))]
 #![allow(rustc::default_hash_types)]
 
 #[macro_use]