Micro-optimize CallableType.__init__

Author: JukkaL

mypy/types.py

@@ -2104,14 +2104,14 @@ def __init__(
     ) -> None:
         super().__init__(line, column)
         assert len(arg_types) == len(arg_kinds) == len(arg_names)
-        for t, k in zip(arg_types, arg_kinds):
+        if variables is None:
+            variables = []
+        self.arg_types = list(arg_types)
+        for t in self.arg_types:
             if isinstance(t, ParamSpecType):
                 assert not t.prefix.arg_types
                 # TODO: should we assert that only ARG_STAR contain ParamSpecType?
                 # See testParamSpecJoin, that relies on passing e.g `P.args` as plain argument.
-        if variables is None:
-            variables = []
-        self.arg_types = list(arg_types)
         self.arg_kinds = arg_kinds
         self.arg_names = list(arg_names)
         self.min_args = arg_kinds.count(ARG_POS)