diff --git a/src/liballoc/benches/lib.rs b/src/liballoc/benches/lib.rs
index 958020d0b0e..5a5eb846b73 100644
--- a/src/liballoc/benches/lib.rs
+++ b/src/liballoc/benches/lib.rs
@@ -14,7 +14,6 @@
 #![feature(rand)]
 #![feature(repr_simd)]
 #![feature(slice_rotate)]
-#![feature(sort_unstable)]
 #![feature(test)]
 
 extern crate test;
diff --git a/src/libcore/tests/lib.rs b/src/libcore/tests/lib.rs
index 337f8aa31dc..b0a57d97d5e 100644
--- a/src/libcore/tests/lib.rs
+++ b/src/libcore/tests/lib.rs
@@ -34,7 +34,6 @@
 #![feature(slice_patterns)]
 #![feature(slice_rotate)]
 #![feature(sort_internals)]
-#![feature(sort_unstable)]
 #![feature(specialization)]
 #![feature(step_by)]
 #![feature(step_trait)]
diff --git a/src/librustc/lib.rs b/src/librustc/lib.rs
index b81c56e5ee8..e4cf893375c 100644
--- a/src/librustc/lib.rs
+++ b/src/librustc/lib.rs
@@ -39,7 +39,6 @@
 #![feature(specialization)]
 #![feature(unboxed_closures)]
 #![feature(discriminant_value)]
-#![feature(sort_unstable)]
 #![feature(trace_macros)]
 #![feature(test)]
 
diff --git a/src/librustc_incremental/lib.rs b/src/librustc_incremental/lib.rs
index 5bd7a24bdaf..ac3149b90b8 100644
--- a/src/librustc_incremental/lib.rs
+++ b/src/librustc_incremental/lib.rs
@@ -20,7 +20,6 @@
 
 #![feature(rand)]
 #![feature(conservative_impl_trait)]
-#![feature(sort_unstable)]
 
 extern crate graphviz;
 #[macro_use] extern crate rustc;
diff --git a/src/librustc_metadata/lib.rs b/src/librustc_metadata/lib.rs
index 12997f24c74..99b718ea07b 100644
--- a/src/librustc_metadata/lib.rs
+++ b/src/librustc_metadata/lib.rs
@@ -26,7 +26,6 @@
 #![feature(specialization)]
 #![feature(discriminant_value)]
 #![feature(rustc_private)]
-#![feature(sort_unstable)]
 
 #[macro_use]
 extern crate log;