--- a/editor/libeditor/TextEditRules.cpp
+++ b/editor/libeditor/TextEditRules.cpp
@@ -1352,16 +1352,19 @@ TextEditRules::RemoveRedundantTrailingBR
   RefPtr<Element> childElement = child->AsElement();
   if (!TextEditUtils::IsMozBR(childElement)) {
     return NS_OK;
   }
 
   // Rather than deleting this node from the DOM tree we should instead
   // morph this br into the bogus node
   childElement->UnsetAttr(kNameSpaceID_None, nsGkAtoms::type, true);
+  if (NS_WARN_IF(!CanHandleEditAction())) {
+    return NS_ERROR_EDITOR_DESTROYED;
+  }
 
   // set mBogusNode to be this <br>
   mBogusNode = childElement;
 
   // give it the bogus node attribute
   childElement->SetAttr(kNameSpaceID_None, kMOZEditorBogusNodeAttrAtom,
                         kMOZEditorBogusNodeValue, false);
   return NS_OK;

--- a/editor/libeditor/TextEditRules.h
+++ b/editor/libeditor/TextEditRules.h
@@ -174,17 +174,17 @@ protected:
                           nsAString* aOutText,
                           uint32_t aFlags,
                           bool* aOutCancel,
                           bool* aHandled);
 
   /**
    * Check for and replace a redundant trailing break.
    */
-  nsresult RemoveRedundantTrailingBR();
+  MOZ_MUST_USE nsresult RemoveRedundantTrailingBR();
 
   /**
    * Creates a trailing break in the text doc if there is not one already.
    */
   MOZ_MUST_USE nsresult CreateTrailingBRIfNeeded();
 
   /**
    * Creates a bogus <br> node if the root element has no editable content.