fix type inference

Author: SunDoge

examples/prog.py

@@ -5,7 +5,7 @@
 @ta.argument_parser(
     description='Process some integers.'
 )
-class Args:
+class Args(ta.TypedArgs):
     integers: List[int] = ta.add_argument(
         metavar='N', type=int, nargs='+',
         help='an integer for the accumulator'

typed_args/__init__.py

@@ -8,7 +8,7 @@
     raise e
 
 
-from ._core import parse_args, parse_known_args, argument_parser
+from ._core import parse_args, parse_known_args, argument_parser, TypedArgs
 from ._parser import add_argument, add_argument_group, add_parser, add_subparsers
 from ._utils import SubcommandEnum, DefaultHelpFormatter
 from argparse import SUPPRESS, OPTIONAL, ZERO_OR_MORE, ONE_OR_MORE, REMAINDER
@@ -17,7 +17,7 @@
 
 __all__ = [
     'dataclass',
-    'parse_args', 'parse_known_args', 'argument_parser',
+    'parse_args', 'parse_known_args', 'argument_parser', 'TypedArgs',
     'add_argument', 'add_argument_group', 'add_parser', 'add_subparsers',
     'SubcommandEnum', 'DefaultHelpFormatter',
     'SUPPRESS', 'OPTIONAL', 'ZERO_OR_MORE', 'ONE_OR_MORE', 'REMAINDER',

typed_args/_core.py

@@ -1,5 +1,5 @@
 import argparse
-from typing import Generic, List, Optional, Sequence, Tuple, Type, TypeVar, overload, Callable
+from typing import List, Optional, Sequence, Tuple, Type, TypeVar, overload, Callable
 import dataclasses
 import logging
 
@@ -42,14 +42,13 @@ def parse_known_args(
     return opts, unknown
 
 
-class _Parsable(Generic[T]):
-
+class TypedArgs:
     @classmethod
-    def parse_args(cls, args: Optional[Sequence[str]] = None, namespace:  Optional[argparse.Namespace] = None) -> T:
+    def parse_args(cls: Type[T], args: Optional[Sequence[str]] = None, namespace:  Optional[argparse.Namespace] = None) -> T:
         pass
 
     @classmethod
-    def parse_known_args(cls, args: Optional[Sequence[str]] = None, namespace:  Optional[argparse.Namespace] = None) -> Tuple[T, List[str]]:
+    def parse_known_args(cls: Type[T], args: Optional[Sequence[str]] = None, namespace:  Optional[argparse.Namespace] = None) -> Tuple[T, List[str]]:
         pass
 
 
@@ -68,12 +67,12 @@ def argument_parser(
     add_help: bool = True,
     allow_abbrev: bool = True,
     exit_on_error: bool = True,
-) -> Callable[[Type[T]], _Parsable[T]]: ...
+) -> Callable[[T], T]: ...
 
 
 def argument_parser(**kwargs):
 
-    def f(klass: Type[T]) -> _Parsable[T]:
+    def f(klass):
         def _make_parser():
             return argparse.ArgumentParser(**kwargs)