Deal with stabilization of `feature(slice_patterns)`
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 29872be..96406bc 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -11,7 +11,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(label_break_value)]
 #![feature(nll)]
-#![feature(slice_patterns)]
+#![cfg_attr(bootstrap, feature(slice_patterns))]
 #![recursion_limit = "256"]
 
 pub use rustc_hir::def::{Namespace, PerNS};