Return empty dict list, do not mutate IR

Author: Wheest

mlir/python/mlir/dialects/func.py

@@ -106,9 +106,7 @@ def add_entry_block(self, arg_locs: Optional[Sequence[Location]] = None):
     @property
     def arg_attrs(self):
         if ARGUMENT_ATTRIBUTE_NAME not in self.attributes:
-            self.attributes[ARGUMENT_ATTRIBUTE_NAME] = ArrayAttr.get(
-                [DictAttr.get({}) for _ in self.type.inputs]
-            )
+            return ArrayAttr.get([DictAttr.get({}) for _ in self.type.inputs])
         return ArrayAttr(self.attributes[ARGUMENT_ATTRIBUTE_NAME])
 
     @arg_attrs.setter