work around python#11612

.mypy/baseline.json

@@ -2041,7 +2041,7 @@
         "code": "truthy-bool",
         "column": 24,
         "message": "\"rvalue_type\" has type \"Type\" which does not implement __bool__ or __len__ so it could always be true in boolean context",
-        "offset": 160,
+        "offset": 140,
         "src": "and rvalue_type",
         "target": "mypy.checker.TypeChecker.check_assignment"
       },
@@ -42258,4 +42258,4 @@
     "package:mypy",
     "package:mypyc"
   ]
-}
+}

mypy/checker.py

@@ -2685,7 +2685,7 @@ class Bar(enum.Enum):
                 def __new__(cls, val): ...
             class Baz(int, Foo, Bar, enum.Flag): ...
         """
-        enum_base: Instance | None = None
+        enum_base = cast(Optional[Instance], None)
         for base in defn.info.bases:
             if enum_base is None and base.type.is_enum:
                 enum_base = base

mypy/modulefinder.py

@@ -21,7 +21,7 @@
 else:
     import tomli as tomllib
 
-from typing import Dict, Final, List, NamedTuple, Optional, Tuple, Union
+from typing import Dict, Final, List, NamedTuple, Optional, Tuple, Union, cast
 from typing_extensions import TypeAlias as _TypeAlias
 
 from mypy import pyinfo
@@ -324,7 +324,7 @@ def _typeshed_has_version(self, module: str) -> bool:
     def _find_module_non_stub_helper(
         self, components: list[str], pkg_dir: str, ignore_missing_py_typed=False
     ) -> OnePackageDir | ModuleNotFoundReason:
-        plausible_match: OnePackageDir | None = None
+        plausible_match = cast(Optional[OnePackageDir], None)
         dir_path = pkg_dir
         for index, component in enumerate(components):
             dir_path = os.path.join(dir_path, component)

mypy/plugins/attrs.py

@@ -4,7 +4,7 @@
 
 from collections import defaultdict
 from functools import reduce
-from typing import Final, Iterable, List, Mapping, cast
+from typing import Final, Iterable, List, Mapping, Optional, cast
 from typing_extensions import Literal
 
 import mypy.plugin  # To avoid circular imports.
@@ -656,7 +656,7 @@ def _parse_converter(
     else:
         is_attr_converters_optional = False
 
-    converter_type: Type | None = None
+    converter_type = cast(Optional[Type], None)
     if isinstance(converter_expr, RefExpr) and converter_expr.node:
         if isinstance(converter_expr.node, FuncDef):
             if converter_expr.node.type and isinstance(converter_expr.node.type, FunctionLike):
@@ -996,7 +996,7 @@ def _get_expanded_attr_types(
     if isinstance(typ, AnyType):
         return None
     elif isinstance(typ, UnionType):
-        ret: list[Mapping[str, Type]] | None = []
+        ret = cast(Optional[List[Mapping[str, Type]]], [])
         for item in typ.relevant_items():
             item = get_proper_type(item)
             item_types = _get_expanded_attr_types(ctx, item, item, parent_typ)

mypy/plugins/dataclasses.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Final, Iterator, Literal
+from typing import TYPE_CHECKING, Final, Iterator, List, Literal, Optional, cast
 
 from mypy import errorcodes, message_registry
 from mypy.expandtype import expand_type, expand_type_by_instance
@@ -996,7 +996,7 @@ def _get_expanded_dataclasses_fields(
     if isinstance(typ, AnyType):
         return None
     elif isinstance(typ, UnionType):
-        ret: list[CallableType] | None = []
+        ret = cast(Optional[List[CallableType]], [])
         for item in typ.relevant_items():
             item = get_proper_type(item)
             item_types = _get_expanded_dataclasses_fields(ctx, item, item, parent_typ)

mypy/semanal.py

@@ -6173,7 +6173,7 @@ def _get_node_for_class_scoped_import(
         # mypyc is absolutely convinced that `symbol_node` narrows to a Var in the following,
         # when it can also be a FuncBase. Once fixed, `f` in the following can be removed.
         # See also https://github.com/mypyc/mypyc/issues/892
-        f: Callable[[object], Any] = lambda x: x
+        f = cast(Callable[[object], Any], lambda x: x)
         if isinstance(f(symbol_node), (Decorator, FuncBase, Var)):
             # For imports in class scope, we construct a new node to represent the symbol and
             # set its `info` attribute to `self.type`.

mypy/server/update.py

@@ -118,7 +118,7 @@
 import re
 import sys
 import time
-from typing import Callable, Final, NamedTuple, Sequence, Union
+from typing import Callable, Final, NamedTuple, Optional, Sequence, Union, cast
 from typing_extensions import TypeAlias as _TypeAlias
 
 from mypy.build import (
@@ -1112,7 +1112,7 @@ def not_found() -> None:
         components = rest.split(".")
     else:
         components = []
-    node: SymbolNode | None = modules[module]
+    node = cast(Optional[SymbolNode], modules[module])
     file: MypyFile | None = None
     active_class = None
     for c in components:

mypy/test/testfinegrained.py

@@ -17,7 +17,7 @@
 import os
 import re
 import unittest
-from typing import Any
+from typing import Any, Dict, cast
 
 import pytest
 
@@ -309,15 +309,18 @@ def maybe_suggest(self, step: int, server: Server, src: str, tmp_dir: str) -> li
             use_fixme = m.group(1) if m else None
             m = re.match("--max-guesses=([0-9]+)", flags)
             max_guesses = int(safe(m.group(1))) if m else None
-            res: dict[str, Any] = server.cmd_suggest(
-                target.strip(),
-                json=json,
-                no_any=no_any,
-                no_errors=no_errors,
-                flex_any=flex_any,
-                use_fixme=use_fixme,
-                callsites=callsites,
-                max_guesses=max_guesses,
+            res = cast(
+                Dict[str, Any],
+                server.cmd_suggest(
+                    target.strip(),
+                    json=json,
+                    no_any=no_any,
+                    no_errors=no_errors,
+                    flex_any=flex_any,
+                    use_fixme=use_fixme,
+                    callsites=callsites,
+                    max_guesses=max_guesses,
+                ),
             )
             val = res["error"] if "error" in res else res["out"] + res["err"]
             if json:
@@ -348,16 +351,19 @@ def maybe_inspect(self, step: int, server: Server, src: str) -> list[str]:
             include_object_attrs = "--include-object-attrs" in flags
             union_attrs = "--union-attrs" in flags
             force_reload = "--force-reload" in flags
-            res: dict[str, Any] = server.cmd_inspect(
-                show,
-                location,
-                verbosity=verbosity,
-                limit=limit,
-                include_span=include_span,
-                include_kind=include_kind,
-                include_object_attrs=include_object_attrs,
-                union_attrs=union_attrs,
-                force_reload=force_reload,
+            res = cast(
+                Dict[str, Any],
+                server.cmd_inspect(
+                    show,
+                    location,
+                    verbosity=verbosity,
+                    limit=limit,
+                    include_span=include_span,
+                    include_kind=include_kind,
+                    include_object_attrs=include_object_attrs,
+                    union_attrs=union_attrs,
+                    force_reload=force_reload,
+                ),
             )
             val = res["error"] if "error" in res else res["out"] + res["err"]
             output.extend(val.strip().split("\n"))

mypy/tvar_scope.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Optional, cast
+
 from mypy.nodes import (
     ParamSpecExpr,
     SymbolTableNode,
@@ -51,7 +53,7 @@ def __init__(
 
     def get_function_scope(self) -> TypeVarLikeScope | None:
         """Get the nearest parent that's a function scope, not a class scope"""
-        it: TypeVarLikeScope | None = self
+        it = cast(Optional[TypeVarLikeScope], self)
         while it is not None and it.is_class_scope:
             it = it.parent
         return it

mypy/types.py

@@ -16,6 +16,7 @@
     Iterable,
     NamedTuple,
     NewType,
+    Optional,
     Sequence,
     TypeVar,
     Union,
@@ -2274,7 +2275,7 @@ def with_normalized_var_args(self) -> Self:
         types_suffix = self.arg_types[var_arg_index + 1 :]
         kinds_suffix = self.arg_kinds[var_arg_index + 1 :]
         names_suffix = self.arg_names[var_arg_index + 1 :]
-        no_name: str | None = None  # to silence mypy
+        no_name = cast(Union[str, None], None)  # to silence mypy
 
         # Now we have something non-trivial to do.
         if unpack_index is None:
@@ -3854,7 +3855,7 @@ def flatten_nested_unions(
 
 
 def find_unpack_in_list(items: Sequence[Type]) -> int | None:
-    unpack_index: int | None = None
+    unpack_index = cast(Optional[int], None)
     for i, item in enumerate(items):
         if isinstance(item, UnpackType):
             # We cannot fail here, so we must check this in an earlier

mypyc/irbuild/expression.py

@@ -7,7 +7,7 @@
 from __future__ import annotations
 
 import math
-from typing import Callable, Sequence
+from typing import Callable, Optional, Sequence, cast
 
 from mypy.nodes import (
     ARG_POS,
@@ -984,7 +984,7 @@ def _visit_display(
         else:
             accepted_items.append((False, builder.accept(item)))
 
-    result: Value | None = None
+    result = cast(Optional[Value], None)
     initial_items = []
     for starred, value in accepted_items:
         if result is None and not starred and is_list:

mypyc/transform/exceptions.py

@@ -11,6 +11,8 @@
 
 from __future__ import annotations
 
+from typing import Optional, cast
+
 from mypyc.ir.func_ir import FuncIR
 from mypyc.ir.ops import (
     ERR_ALWAYS,
@@ -43,7 +45,7 @@ def insert_exception_handling(ir: FuncIR) -> None:
     # Generate error block if any ops may raise an exception. If an op
     # fails without its own error handler, we'll branch to this
     # block. The block just returns an error value.
-    error_label: BasicBlock | None = None
+    error_label = cast(Optional[BasicBlock], None)
     for block in ir.blocks:
         adjust_error_kinds(block)
         if error_label is None and any(op.can_raise() for op in block.ops):