1 files changed, 7 insertions, 0 deletions
diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 9e048161633..26c59bdb8ec 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -127,6 +127,7 @@ use std::cell::{Cell, Ref, RefMut};
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::default::Default;
+use std::fmt;
 use std::mem;
 use std::ptr::NonNull;
 use std::rc::Rc;
@@ -213,6 +214,12 @@ struct StyleSheetInDocument {
     owner: Dom<Element>,
 }
 
+impl fmt::Debug for StyleSheetInDocument {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        self.sheet.fmt(formatter)
+    }
+}
+
 impl PartialEq for StyleSheetInDocument {
     fn eq(&self, other: &Self) -> bool {
         Arc::ptr_eq(&self.sheet, &other.sheet)