diff --git a/components/style/dom.rs b/components/style/dom.rs
index c70a8fd26be..c85ff1edaff 100644
--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@@ -151,7 +151,7 @@ pub trait TNode: Sized + Copy + Clone + Debug + NodeInfo + PartialEq {
     /// Get this node's first child.
     fn first_child(&self) -> Option<Self>;
 
-    /// Get this node's first child.
+    /// Get this node's last child.
     fn last_child(&self) -> Option<Self>;
 
     /// Get this node's previous sibling.
diff --git a/components/style/gecko/wrapper.rs b/components/style/gecko/wrapper.rs
index 3f23981a823..476e710795d 100644
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@@ -409,9 +409,11 @@ impl<'ln> TNode for GeckoNode<'ln> {
     #[inline]
     fn prev_sibling(&self) -> Option<Self> {
         unsafe {
-            bindings::Gecko_GetPreviousSibling(self.0)
-                .as_ref()
-                .map(GeckoNode)
+            let prev_or_last = GeckoNode::from_content(self.0.mPreviousOrLastSibling.as_ref()?);
+            if prev_or_last.0.mNextSibling.raw::<nsIContent>().is_null() {
+                return None;
+            }
+            Some(prev_or_last)
         }
     }