diff --git a/mk/tests.mk b/mk/tests.mk
index 744f17531d6..ed6e2b00344 100644
--- a/mk/tests.mk
+++ b/mk/tests.mk
@@ -26,7 +26,7 @@ TEST_TARGET_CRATES = $(filter-out core rustc_unicode alloc_system libc \
 		     		  alloc_jemalloc,$(TARGET_CRATES)) \
 			collectionstest coretest
 TEST_DOC_CRATES = $(DOC_CRATES) arena flate fmt_macros getopts graphviz \
-                log rand rbml
+                log rand rbml serialize
 TEST_HOST_CRATES = $(filter-out rustc_typeck rustc_borrowck rustc_resolve \
 		   		rustc_trans rustc_lint,\
                      $(HOST_CRATES))
diff --git a/src/libserialize/json.rs b/src/libserialize/json.rs
index 452feed3cdb..9e1e3c6a558 100644
--- a/src/libserialize/json.rs
+++ b/src/libserialize/json.rs
@@ -77,8 +77,9 @@
 //! serialization API, using the derived serialization code.
 //!
 //! ```rust
-//! extern crate serialize;
-//! use serialize::json;
+//! # #![feature(rustc_private)]
+//! extern crate serialize as rustc_serialize; // for the deriving below
+//! use rustc_serialize::json;
 //!
 //! // Automatically generate `Decodable` and `Encodable` trait implementations
 //! #[derive(RustcDecodable, RustcEncodable)]
@@ -111,6 +112,7 @@
 //! ### Simple example of `ToJson` usage
 //!
 //! ```rust
+//! # #![feature(rustc_private)]
 //! extern crate serialize;
 //! use serialize::json::{self, ToJson, Json};
 //!
@@ -150,6 +152,7 @@
 //! ### Verbose example of `ToJson` usage
 //!
 //! ```rust
+//! # #![feature(rustc_private)]
 //! extern crate serialize;
 //! use std::collections::BTreeMap;
 //! use serialize::json::{self, Json, ToJson};
@@ -185,7 +188,7 @@
 //!     let json_str: String = json_obj.to_string();
 //!
 //!     // Deserialize like before
-//!     let decoded: TestStruct = json::decode(json_str)).unwrap();
+//!     let decoded: TestStruct = json::decode(&json_str).unwrap();
 //! }
 //! ```
 
diff --git a/src/libserialize/lib.rs b/src/libserialize/lib.rs
index 5b7bec41723..4a766f14531 100644
--- a/src/libserialize/lib.rs
+++ b/src/libserialize/lib.rs
@@ -26,7 +26,8 @@ Core encoding and decoding interfaces.
 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
-       html_playground_url = "https://play.rust-lang.org/")]
+       html_playground_url = "https://play.rust-lang.org/",
+       test(attr(allow(unused_variables), deny(warnings))))]
 
 #![feature(box_syntax)]
 #![feature(collections)]