diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index 8025dfd..b10615c 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -106,7 +106,7 @@ __all__ = [ # legitimate imports of those modules. -def _type_check(arg, msg): +def _type_check(arg, msg, is_argument=False): """Check that the argument is a type, and return it (internal helper). As a special case, accept None and return type(None) instead. Also wrap strings @@ -118,12 +118,16 @@ def _type_check(arg, msg): We append the repr() of the actual value (truncated to 100 chars). """ + invalid_generic_forms = (Generic, _Protocol) + if not is_argument: + invalid_generic_forms = invalid_generic_forms + (ClassVar, ) + if arg is None: return type(None) if isinstance(arg, str): return ForwardRef(arg) if (isinstance(arg, _GenericAlias) and - arg.__origin__ in (Generic, _Protocol, ClassVar)): + arg.__origin__ in invalid_generic_forms): raise TypeError(f"{arg} is not valid as type argument") if (isinstance(arg, _SpecialForm) and arg is not Any or arg in (Generic, _Protocol)): @@ -464,9 +468,10 @@ class ForwardRef(_Final, _root=True): """Internal wrapper to hold a forward reference.""" __slots__ = ('__forward_arg__', '__forward_code__', - '__forward_evaluated__', '__forward_value__') + '__forward_evaluated__', '__forward_value__', + '__forward_is_argument__') - def __init__(self, arg): + def __init__(self, arg, is_argument=False): if not isinstance(arg, str): raise TypeError(f"Forward reference must be a string -- got {arg!r}") try: @@ -477,6 +482,7 @@ class ForwardRef(_Final, _root=True): self.__forward_code__ = code self.__forward_evaluated__ = False self.__forward_value__ = None + self.__forward_is_argument__ = is_argument def _evaluate(self, globalns, localns): if not self.__forward_evaluated__ or localns is not globalns: @@ -488,7 +494,8 @@ class ForwardRef(_Final, _root=True): localns = globalns self.__forward_value__ = _type_check( eval(self.__forward_code__, globalns, localns), - "Forward references must evaluate to types.") + "Forward references must evaluate to types.", + is_argument=self.__forward_is_argument__) self.__forward_evaluated__ = True return self.__forward_value__ @@ -998,7 +1005,7 @@ def get_type_hints(obj, globalns=None, localns=None): if value is None: value = type(None) if isinstance(value, str): - value = ForwardRef(value) + value = ForwardRef(value, is_argument=True) value = _eval_type(value, base_globals, localns) hints[name] = value return hints |