Port ArgKind hack

Author: ilevkivskyi

mypy/nodes.py

@@ -1054,7 +1054,7 @@ def read(cls, data: BytesIO) -> FuncDef:
         read_flags(data, ret, FUNCDEF_FLAGS)
         # NOTE: ret.info is set in the fixup phase.
         ret.arg_names = read_str_opt_list(data)
-        ret.arg_kinds = [ArgKind(ak) for ak in read_int_list(data)]
+        ret.arg_kinds = [ARG_KINDS[ak] for ak in read_int_list(data)]
         ret.abstract_status = read_int(data)
         if read_int(data) == OPT_YES:
             ret.dataclass_transform_spec = DataclassTransformSpec.read(data)

mypy/types.py

@@ -2010,7 +2010,9 @@ def write(self, data: BytesIO) -> None:
     def read(cls, data: BytesIO) -> Parameters:
         return Parameters(
             read_type_list(data),
-            [ArgKind(ak) for ak in read_int_list(data)],
+            # This is a micro-optimization until mypyc gets dedicated enum support. Otherwise,
+            # we would spend ~20% of types deserialization time in Enum.__call__().
+            [ARG_KINDS[ak] for ak in read_int_list(data)],
             read_str_opt_list(data),
             variables=cast(list[TypeVarLikeType], read_type_list(data)),
             imprecise_arg_kinds=read_bool(data),
@@ -2539,7 +2541,7 @@ def read(cls, data: BytesIO) -> CallableType:
         fallback = Instance.read(data)
         return CallableType(
             read_type_list(data),
-            [ArgKind(ak) for ak in read_int_list(data)],
+            [ARG_KINDS[ak] for ak in read_int_list(data)],
             read_str_opt_list(data),
             read_type(data),
             fallback,