1 files changed, 2 insertions, 1 deletions
diff --git a/parser/html/nsHtml5TreeOperation.cpp b/parser/html/nsHtml5TreeOperation.cpp
index d747f80a8..22c805859 100644
--- a/parser/html/nsHtml5TreeOperation.cpp
+++ b/parser/html/nsHtml5TreeOperation.cpp
@@ -433,8 +433,9 @@ nsHtml5TreeOperation::CreateHTMLElement(
       RefPtr<nsIAtom> typeAtom =
         isValue.IsEmpty() ? tagAtom : NS_Atomize(isValue);
 
+      MOZ_ASSERT(nodeInfo->NameAtom()->Equals(nodeInfo->LocalName()));
       definition = nsContentUtils::LookupCustomElementDefinition(document,
-        nodeInfo->LocalName(), nodeInfo->NamespaceID(), typeAtom);
+        nodeInfo->NameAtom(), nodeInfo->NamespaceID(), typeAtom);
 
       if (definition) {
         willExecuteScript = true;