--- a/dom/bindings/Codegen.py
+++ b/dom/bindings/Codegen.py
@@ -13818,16 +13818,21 @@ class CGDictionary(CGThing):
             # Strings are always OK.
             return True
 
         if type.isPrimitive():
             # Primitives (numbers and booleans) are ok, as long as
             # they're not unrestricted float/double.
             return not type.isFloat() or not type.isUnrestricted()
 
+        if type.isRecord():
+            # Records are okay, as long as the value type is.
+            # Per spec, only strings are allowed as keys.
+            return CGDictionary.typeSafeToJSONify(type.inner)
+
         return False
 
     @staticmethod
     def dictionarySafeToJSONify(dictionary):
         # The dictionary itself is OK, so we're good if all our types are.
         return all(CGDictionary.typeSafeToJSONify(m.type)
                    for m in dictionary.members)