Change to evaluate ForwardRefs use typing._eval_type

runtype/dataclass.py

@@ -6,8 +6,8 @@
 from copy import copy
 import dataclasses
 import typing
-from typing import Union, Any, Callable, TypeVar, Dict, Optional, overload
-from typing import TYPE_CHECKING, ClassVar, Type
+from typing import Union, Callable, TypeVar, Dict, Optional, overload
+from typing import TYPE_CHECKING, Type, ForwardRef
 from abc import ABC, abstractmethod
 import inspect
 import types
@@ -16,12 +16,10 @@
 if TYPE_CHECKING:
     from typing_extensions import dataclass_transform
 else:
-
     def dataclass_transform(*a, **kw):
         return lambda f: f
 
 
-from .utils import ForwardRef
 from .common import CHECK_TYPES
 from .validation import TypeMismatchError, ensure_isa as default_ensure_isa
 from .pytypes import TypeCaster, SumType, NoneType, ATypeCaster, PythonType, type_caster

runtype/pytypes.py

@@ -15,20 +15,11 @@
 from datetime import datetime, date, time, timedelta
 from types import FrameType
 
-from .utils import ForwardRef
 from .base_types import DataType, Validator, TypeMismatchError, dp, Variance
 from . import base_types
 from . import datetime_parse
 
 
-if sys.version_info < (3, 9):
-    _orig_eval = ForwardRef._evaluate
-
-    def _forwardref_evaluate(self, glob, loc, _):
-        return _orig_eval(self, glob, loc)
-else:
-    _forwardref_evaluate = ForwardRef._evaluate
-
 try:
     import typing_extensions
 except ImportError:
@@ -526,10 +517,10 @@ def _to_canon(self, t):
         if isinstance(t, (base_types.Type, Validator)):
             return t
 
-        if isinstance(t, ForwardRef):
+        if isinstance(t, typing.ForwardRef):
             if self.frame is None:
                 raise RuntimeError("Cannot resolve ForwardRef: TypeCaster initialized without a frame")
-            t = _forwardref_evaluate(t, self.frame.f_globals, self.frame.f_locals, frozenset())
+            t = typing._eval_type(t, self.frame.f_globals, self.frame.f_locals)
 
         if isinstance(t, tuple):
             return SumType.create([to_canon(x) for x in t])

runtype/utils.py

@@ -1,10 +1,7 @@
 import inspect
-import sys
 import contextvars
 from contextlib import contextmanager
 
-from typing import ForwardRef as ForwardRef
-
 def get_func_signatures(typesystem, f):
     sig = inspect.signature(f)
     typesigs = []