--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -4189,20 +4189,17 @@ Element::ClearServoData(nsIDocument* aDo
   MOZ_ASSERT(aDoc);
 #ifdef MOZ_STYLO
   Servo_Element_ClearData(this);
   // Since this element is losing its servo data, nothing under it may have
   // servo data either, so we can forget restyles rooted at this element. This
   // is necessary for correctness, since we invoke ClearServoData in various
   // places where an element's flattened tree parent changes, and such a change
   // may also make an element invalid to be used as a restyle root.
-  //
-  // Note that we need to null-check aDoc, which may be null in some situations
-  // when invoked from UnbindFromTree.
-  if (aDoc && aDoc->GetServoRestyleRoot() == this) {
+  if (aDoc->GetServoRestyleRoot() == this) {
     aDoc->ClearServoRestyleRoot();
   }
 #else
   MOZ_CRASH("Accessing servo node data in non-stylo build");
 #endif
 }
 
 void