--- a/dom/bindings/parser/WebIDL.py
+++ b/dom/bindings/parser/WebIDL.py
@@ -2292,19 +2292,16 @@ class IDLMozMapType(IDLParameterizedType
         return isinstance(other, IDLMozMapType) and self.inner == other.inner
 
     def __str__(self):
         return self.inner.__str__() + "MozMap"
 
     def isMozMap(self):
         return True
 
-    def isExposedInAllOf(self, exposureSet):
-        return self.inner.unroll().isExposedInAllOf(exposureSet)
-
     def tag(self):
         return IDLType.Tags.mozmap
 
     def complete(self, scope):
         self.inner = self.inner.complete(scope)
         self.name = self.inner.name + "MozMap"
         return self
 
@@ -2312,16 +2309,19 @@ class IDLMozMapType(IDLParameterizedType
         if other.isPromise():
             return False
         if other.isUnion():
             # Just forward to the union; it'll deal
             return other.isDistinguishableFrom(self)
         return (other.isPrimitive() or other.isString() or other.isEnum() or
                 other.isDate() or other.isNonCallbackInterface() or other.isSequence())
 
+    def isExposedInAllOf(self, exposureSet):
+        return self.inner.unroll().isExposedInAllOf(exposureSet)
+
 
 class IDLUnionType(IDLType):
     def __init__(self, location, memberTypes):
         IDLType.__init__(self, location, "")
         self.memberTypes = memberTypes
         self.hasNullableType = False
         self._dictionaryType = None
         self.flatMemberTypes = None