diff --git a/layout/base/ServoRestyleManager.cpp b/layout/base/ServoRestyleManager.cpp
index a74abe1d4363..e2de2d285833 100644
--- a/layout/base/ServoRestyleManager.cpp
+++ b/layout/base/ServoRestyleManager.cpp
@@ -366,6 +366,15 @@ ServoRestyleManager::ProcessPendingRestyles()
       ServoElementSnapshot* snapshot = iter.UserData();
       Element* element = iter.Key();
 
+      // The element is no longer in the document, so don't bother computing
+      // a final restyle hint for it.
+      //
+      // XXXheycam RestyleTracker checks that the element's GetComposedDoc()
+      // matches the document we're restyling.  Do we need to do that too?
+      if (!element->IsInComposedDoc()) {
+        continue;
+      }
+
       // TODO: avoid the ComputeRestyleHint call if we already have the highest
       // explicit restyle hint?
       nsRestyleHint hint = styleSet->ComputeRestyleHint(element, snapshot);
diff --git a/layout/style/crashtests/1315889-1.html b/layout/style/crashtests/1315889-1.html
new file mode 100644
index 000000000000..29186fac1c47
--- /dev/null
+++ b/layout/style/crashtests/1315889-1.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<style>
+.x { color: blue; }
+</style>
+<div class=x>hello</div>
+<script>
+document.body.offsetWidth;
+var x = document.querySelector(".x");
+x.className = "";
+x.remove();
+document.body.offsetWidth;
+</script>
diff --git a/layout/style/crashtests/crashtests.list b/layout/style/crashtests/crashtests.list
index 1be03042c13f..7a7752c81372 100644
--- a/layout/style/crashtests/crashtests.list
+++ b/layout/style/crashtests/crashtests.list
@@ -160,4 +160,5 @@ pref(dom.animations-api.core.enabled,true) load 1290994-2.html
 pref(dom.animations-api.core.enabled,true) load 1290994-3.html
 load 1290994-4.html
 load 1314531.html
+load 1315889-1.html
 load 1315894-1.html
