Use --no-implicit-optional for type checking

parso/grammar.py

@@ -47,15 +47,15 @@ def __init__(self, text: str, *, tokenizer, parser=BaseParser, diff_parser=None)
  self._hashed = hashlib.sha256(text.encode("utf-8")).hexdigest()
 
  def parse(self,
- code: Union[str, bytes] = None,
+ code: Optional[Union[str, bytes]] = None,
  *,
  error_recovery=True,
- path: Union[os.PathLike, str] = None,
- start_symbol: str = None,
+ path: Optional[Union[os.PathLike, str]] = None,
+ start_symbol: Optional[str] = None,
  cache=False,
  diff_cache=False,
- cache_path: Union[os.PathLike, str] = None,
- file_io: FileIO = None) -> _NodeT:
+ cache_path: Optional[Union[os.PathLike, str]] = None,
+ file_io: Optional[FileIO] = None) -> _NodeT:
  """
  If you want to parse a Python file you want to start here, most likely.
 
@@ -231,7 +231,7 @@ def _tokenize(self, code):
  return tokenize(code, version_info=self.version_info)
 
 
-def load_grammar(*, version: str = None, path: str = None):
+def load_grammar(*, version: Optional[str] = None, path: Optional[str] = None):
  """
  Loads a :py:class:`parso.Grammar`. The default version is the current Python
  version.

parso/python/tokenize.py

@@ -16,7 +16,7 @@
 import itertools as _itertools
 from codecs import BOM_UTF8
 from typing import NamedTuple, Tuple, Iterator, Iterable, List, Dict, \
- Pattern, Set
+ Pattern, Set, Optional
 
 from parso.python.token import PythonTokenTypes
 from parso.utils import split_lines, PythonVersionInfo, parse_version_string
@@ -364,7 +364,7 @@ def tokenize_lines(
  lines: Iterable[str],
  *,
  version_info: PythonVersionInfo,
- indents: List[int] = None,
+ indents: Optional[List[int]] = None,
  start_pos: Tuple[int, int] = (1, 0),
  is_first_token=True,
 ) -> Iterator[PythonToken]:

parso/utils.py

@@ -2,7 +2,7 @@
 import sys
 from ast import literal_eval
 from functools import total_ordering
-from typing import NamedTuple, Sequence, Union
+from typing import Optional, NamedTuple, Sequence, Union
 
 # The following is a list in Python that are line breaks in str.splitlines, but
 # not in Python. In Python only \r (Carriage Return, 0xD) and \n (Line Feed,
@@ -180,7 +180,7 @@ def _parse_version(version) -> PythonVersionInfo:
  return PythonVersionInfo(major, minor)
 
 
-def parse_version_string(version: str = None) -> PythonVersionInfo:
+def parse_version_string(version: Optional[str] = None) -> PythonVersionInfo:
  """
  Checks for a valid version number (e.g. `3.8` or `3.10.1` or `3`) and
  returns a corresponding version info that is always two characters long in

setup.cfg

@@ -23,3 +23,4 @@ warn_unused_configs = True
 warn_unreachable = True
 
 strict_equality = True
+no_implicit_optional = True

test/normalizer_issue_files/python.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-from typing import ClassVar, List
+from typing import Optional, ClassVar, List
 
 print(1, 2)
 
@@ -62,8 +62,8 @@ async def f(x): return 2
 
 # Annotated Function Definitions
 # Okay
-def munge(input: AnyStr, sep: AnyStr = None, limit=1000,
- extra: Union[str, dict] = None) -> AnyStr:
+def munge(input: AnyStr, sep: Optional[AnyStr] = None, limit=1000,
+ extra: Optional[Union[str, dict]] = None) -> AnyStr:
  pass