Fix flake8 errors

This is a combination of:
- Fixing some issues upstream.
- Modifying our cleanup script to carry over noqa comments, and
  copying over the new versions of some files.
- A small addition to our flake8 config.

.flake8

@@ -86,6 +86,7 @@ ignore =
   # I think these are internal to pycodestyle?
   # E901,  # SyntaxError or IndentationError
   # E902,  # IOError
+  F811,  # isn't aware of type-only imports, results in false-positives
   W191,  # indentation contains tabs
   W291,  # trailing whitespace; is same as TXT6 (Trailing Whitespace).
   W292,  # no newline at end of file; is same as TXT4 (File Does Not End in

libcst/_type_enforce.py

@@ -15,7 +15,7 @@ except ImportError:  # py36
     from typing import _ForwardRef as ForwardRef
 
 
-def is_value_of_type(
+def is_value_of_type(  # noqa: C901 "too complex"
     value: Any, expected_type: Any, invariant_check: bool = False
 ) -> bool:
     """

libcst/batched_visitor.py

@@ -25,7 +25,7 @@ from libcst.visitors import CSTNodeT, CSTVisitor
 
 
 if TYPE_CHECKING:
-    from libcst.metadata.base_provider import BaseMetadataProvider
+    from libcst.metadata.base_provider import BaseMetadataProvider  # noqa: F401
 
 
 VisitorMethod = Callable[[cst.CSTNode], None]

libcst/metadata/_interface.py

@@ -10,8 +10,8 @@ from typing import TYPE_CHECKING, ClassVar, Sequence, Type, TypeVar
 
 if TYPE_CHECKING:
     # Circular dependency for typing reasons only
-    from libcst.nodes._base import CSTNode
-    from libcst.metadata.base_provider import BaseMetadataProvider
+    from libcst.nodes._base import CSTNode  # noqa: F401
+    from libcst.metadata.base_provider import BaseMetadataProvider  # noqa: F401
 
 
 _T = TypeVar("_T")

libcst/nodes/__init__.py

@@ -14,9 +14,9 @@ grammar in a whitespace-sensitive fashion, forming a "Concrete" Syntax Tree (CST
 # implementation details. Those base classes shouldn't be useful outside of this
 # package.
 
-from libcst.nodes._base import CSTNode, CSTValidationError
-from libcst.nodes._dummy import DummyNode
-from libcst.nodes._expression import (
+from libcst.nodes._base import CSTNode, CSTValidationError  # noqa: F401
+from libcst.nodes._dummy import DummyNode  # noqa: F401
+from libcst.nodes._expression import (  # noqa: F401
     Annotation,
     Arg,
     Asynchronous,
@@ -75,8 +75,8 @@ from libcst.nodes._expression import (
     UnaryOperation,
     Yield,
 )
-from libcst.nodes._module import Module
-from libcst.nodes._op import (
+from libcst.nodes._module import Module  # noqa: F401
+from libcst.nodes._op import (  # noqa: F401
     Add,
     AddAssign,
     And,
@@ -131,7 +131,7 @@ from libcst.nodes._op import (
     Subtract,
     SubtractAssign,
 )
-from libcst.nodes._statement import (
+from libcst.nodes._statement import (  # noqa: F401
     AnnAssign,
     AsName,
     Assert,
@@ -170,7 +170,7 @@ from libcst.nodes._statement import (
     With,
     WithItem,
 )
-from libcst.nodes._whitespace import (
+from libcst.nodes._whitespace import (  # noqa: F401
     Comment,
     EmptyLine,
     Newline,

libcst/nodes/_base.py

@@ -26,7 +26,7 @@ from libcst.visitors import CSTTransformer, CSTVisitor, CSTVisitorT
 
 
 if TYPE_CHECKING:
-    from libcst.metadata.base_provider import BaseMetadataProvider
+    from libcst.metadata.base_provider import BaseMetadataProvider  # noqa: F401
 
 
 _T = TypeVar("_T")

libcst/nodes/_dummy.py

@@ -13,7 +13,7 @@ from libcst._removal_sentinel import RemovalSentinel
 from libcst.nodes._base import CSTNode, CSTValidationError
 from libcst.nodes._expression import LeftParen, RightParen
 from libcst.nodes._internal import CodegenState, visit_sequence
-from libcst.nodes._whitespace import EmptyLine, TrailingWhitespace
+from libcst.nodes._whitespace import EmptyLine, TrailingWhitespace  # noqa: F401
 from libcst.visitors import CSTVisitorT
 
 

libcst/nodes/_internal.py

@@ -29,9 +29,9 @@ from libcst._removal_sentinel import RemovalSentinel
 
 if TYPE_CHECKING:
     # These are circular dependencies only used for typing purposes
-    from libcst.nodes._base import CSTNode
+    from libcst.nodes._base import CSTNode  # noqa: F401
     from libcst.visitors import CSTVisitorT
-    from libcst.metadata.position_provider import (
+    from libcst.metadata.position_provider import (  # noqa: F401
         BasicPositionProvider,
         SyntacticPositionProvider,
     )

libcst/nodes/_module.py

@@ -22,7 +22,7 @@ from libcst.visitors import CSTVisitorT
 
 if TYPE_CHECKING:
     # These are circular dependencies only used for typing purposes
-    from libcst.metadata.position_provider import (
+    from libcst.metadata.position_provider import (  # noqa: F401
         BasicPositionProvider,
         SyntacticPositionProvider,
     )

libcst/nodes/_whitespace.py

@@ -41,7 +41,7 @@ class BaseParenthesizableWhitespace(CSTNode, ABC):
 
     https://docs.python.org/3/reference/lexical_analysis.html#implicit-line-joining
 
-    ParenthesizableWhitespace may contain a backslash character (`\`), when used as a
+    ParenthesizableWhitespace may contain a backslash character (`\\`), when used as a
     line-continuation character. While the continuation character isn't technically
     "whitespace", it serves the same purpose.
 
@@ -84,7 +84,7 @@ class Newline(BaseLeaf):
     TrailingWhitespace).
 
     Other newlines may occur in the document after continuation characters (the
-    backslash, `\`), but those newlines are treated as part of the SimpleWhitespace.
+    backslash, `\\`), but those newlines are treated as part of the SimpleWhitespace.
     """
 
     # A value of 'None' indicates that the module's default newline sequence should be

libcst/parser/_conversions/params.py

@@ -14,7 +14,7 @@ from libcst.parser._types.partials import ParamStarPartial
 from libcst.parser._whitespace_parser import parse_parenthesizable_whitespace
 
 
-@with_production(
+@with_production(  # noqa: C901: too complex
     "typedargslist",
     (
         "(tfpdef_assign (',' tfpdef_assign)* "

libcst/parser/_types/partials.py

@@ -6,7 +6,6 @@
 # pyre-strict
 
 from dataclasses import dataclass
-from enum import Enum
 from typing import Generic, Optional, Sequence, TypeVar, Union
 
 import libcst.nodes as cst

libcst/parser/_wrapped_tokenize.py

@@ -105,7 +105,7 @@ def tokenize_lines(
         yield _convert_token(state, curr_token, None)
 
 
-def _convert_token(
+def _convert_token(  # noqa: C901: too complex
     state: _TokenizeState, curr_token: OrigToken, next_token: Optional[OrigToken]
 ) -> Token:
     ct_type = curr_token.type

libcst/tool.py

@@ -9,7 +9,6 @@
 # python -m libcst.tool print python_file.py
 
 # pyre-strict
-
 import argparse
 import dataclasses
 import sys
@@ -23,7 +22,7 @@ from libcst.parser import parse_module
 _DEFAULT_INDENT: str = "  "
 
 
-def _node_repr_recursive(
+def _node_repr_recursive(  # noqa: C901
     node: object,
     *,
     indent: str = _DEFAULT_INDENT,