3 files changed, 37 insertions, 27 deletions
diff --git a/components/script/dom/bindings/conversions.rs b/components/script/dom/bindings/conversions.rs
index 710a5715fa4..c8f3b986623 100644
--- a/components/script/dom/bindings/conversions.rs
+++ b/components/script/dom/bindings/conversions.rs
@@ -34,6 +34,7 @@
 
 use core::nonzero::NonZero;
 use dom::bindings::error::throw_type_error;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::num::Finite;
 use dom::bindings::str::{ByteString, USVString};
@@ -107,32 +108,6 @@ pub trait IDLInterface {
     fn derives(&'static DOMClass) -> bool;
 }
 
-/// A trait to hold the cast functions of IDL interfaces that either derive
-/// or are derived from other interfaces.
-pub trait Castable: IDLInterface + Reflectable + Sized {
-    /// Check whether a DOM object implements one of its deriving interfaces.
-    fn is<T>(&self) -> bool where T: DerivedFrom<Self> {
-        let class = unsafe {
-            get_dom_class(self.reflector().get_jsobject().get()).unwrap()
-        };
-        T::derives(class)
-    }
-
-    /// Cast a DOM object upwards to one of the interfaces it derives from.
-    fn upcast<T>(&self) -> &T where T: Castable, Self: DerivedFrom<T> {
-        unsafe { mem::transmute(self) }
-    }
-
-    /// Cast a DOM object downwards to one of the interfaces it might implement.
-    fn downcast<T>(&self) -> Option<&T> where T: DerivedFrom<Self> {
-        if self.is::<T>() {
-            Some(unsafe { mem::transmute(self) })
-        } else {
-            None
-        }
-    }
-}
-
 /// A trait to mark an IDL interface as deriving from another one.
 #[rustc_on_unimplemented = "The IDL interface `{Self}` is not derived from `{T}`."]
 pub trait DerivedFrom<T: Castable>: Castable {}
diff --git a/components/script/dom/bindings/inheritance.rs b/components/script/dom/bindings/inheritance.rs
new file mode 100644
index 00000000000..5878c44c5f3
--- /dev/null
+++ b/components/script/dom/bindings/inheritance.rs
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+
+use dom::bindings::conversions::get_dom_class;
+use dom::bindings::conversions::{DerivedFrom, IDLInterface};
+use dom::bindings::utils::Reflectable;
+use std::mem;
+
+/// A trait to hold the cast functions of IDL interfaces that either derive
+/// or are derived from other interfaces.
+pub trait Castable: IDLInterface + Reflectable + Sized {
+    /// Check whether a DOM object implements one of its deriving interfaces.
+    fn is<T>(&self) -> bool where T: DerivedFrom<Self> {
+        let class = unsafe {
+            get_dom_class(self.reflector().get_jsobject().get()).unwrap()
+        };
+        T::derives(class)
+    }
+
+    /// Cast a DOM object upwards to one of the interfaces it derives from.
+    fn upcast<T>(&self) -> &T where T: Castable, Self: DerivedFrom<T> {
+        unsafe { mem::transmute(self) }
+    }
+
+    /// Cast a DOM object downwards to one of the interfaces it might implement.
+    fn downcast<T>(&self) -> Option<&T> where T: DerivedFrom<Self> {
+        if self.is::<T>() {
+            Some(unsafe { mem::transmute(self) })
+        } else {
+            None
+        }
+    }
+}
diff --git a/components/script/dom/bindings/js.rs b/components/script/dom/bindings/js.rs
index a6af7680a96..388a8ba81ef 100644
--- a/components/script/dom/bindings/js.rs
+++ b/components/script/dom/bindings/js.rs
@@ -24,7 +24,8 @@
 //!
 
 use core::nonzero::NonZero;
-use dom::bindings::conversions::{Castable, DerivedFrom};
+use dom::bindings::conversions::DerivedFrom;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::trace::JSTraceable;
 use dom::bindings::trace::trace_reflector;
 use dom::bindings::utils::{Reflectable, Reflector};