rollup merge of #20723: pnkfelix/feature-gate-box-syntax

Conflicts:
	src/compiletest/compiletest.rs
	src/libcollections/lib.rs
	src/libserialize/lib.rs
	src/libsyntax/feature_gate.rs

1 files changed, 3 insertions, 0 deletions

diff --git a/src/liblog/lib.rs b/src/liblog/lib.rs
index 036663ad8f5..0d5f6b65827 100644
--- a/src/liblog/lib.rs
+++ b/src/liblog/lib.rs
@@ -164,7 +164,10 @@
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/nightly/",
        html_playground_url = "http://play.rust-lang.org/")]
+
+#![allow(unknown_features)]
 #![feature(slicing_syntax)]
+#![feature(box_syntax)]
 #![deny(missing_docs)]
 
 extern crate regex;