diff --git a/components/script/dom/bindings/conversions.rs b/components/script/dom/bindings/conversions.rs
index 30bc810e44f..9cd7684b335 100644
--- a/components/script/dom/bindings/conversions.rs
+++ b/components/script/dom/bindings/conversions.rs
@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#![deny(missing_doc)]
+
 //! Conversions of Rust values to and from `JSVal`.
 
 use dom::bindings::js::{JS, JSRef, Root};
@@ -29,10 +31,15 @@ use std::slice;
 
 use dom::bindings::codegen::PrototypeList;
 
+/// A trait to retrieve the constants necessary to check if a `JSObject`
+/// implements a given interface.
 // FIXME (https://github.com/rust-lang/rfcs/pull/4)
 //       remove Option<Self> arguments.
 pub trait IDLInterface {
+    /// Returns the prototype ID.
     fn get_prototype_id(_: Option<Self>) -> PrototypeList::id::ID;
+    /// Returns the prototype depth, i.e., the number of interfaces this
+    /// interface inherits from.
     fn get_prototype_depth(_: Option<Self>) -> uint;
 }