Bug Fixes:

• Fixed a recent regression that results in incorrect type evaluation when using a two-argument form of super() and the second argument is type[Self].
• Fixed a recent regression that results in a false positive type error when converting certain constructors (such as for the class defaultdict) to a callable type.
• Fixed recent regression that results in a false positive under certain specific circumstances involving higher-order functions that return generic callable types.
• Fixed a bug that results in a false positive error during protocol matching because writable class variables defined in a named tuple or a frozen dataclass were considered read-only.
• Fixed a bug that causes incorrect type narrowing of expressions used within a tuple expression in the subject expression of a match statement.
• Fixed a bug that results in an incorrect type evaluation of a higher-order function that is passed an overloaded function.
• Fixed recent regression that results in a false positive error under very specific circumstances involving a function with a TypeVar used in both a contravariant and covariant context and combined by union with other types in the contravariant context.
• Fixed a bug that leads to a false positive "default value is specified as ..." when using --verifytypes and the function has a decorator applied that uses a ParamSpec.
• Simplified check for unnecessary isinstance call. Removed a bunch of redundant code and fixed a number of bugs in the process.
• Fixed a bug that leads to incorrect type narrowing with isinstance or TypeIs when the filter type (the second argument to isinstance) is a subclass of type.
• Fixed bug that results in incorrect type narrowing for the in (containment) operator when the filter includes class objects (instances of type).
• Fixed a bug that results in incorrect type narrowing for the x is ... (ellipsis) type guard pattern.
• Fixed a bug in the stub generator so it properly outputs type aliases that use the PEP 613 TypeAlias qualifier.
• Fixed bug that causes a crash in the language server under certain circumstances with partially-written code that has syntax errors.
• Fixed a bug that results in incorrect type narrowing for TypeIs when it is used with a Callable type form.
• Fixed several inconsistencies and bugs in the isinstance type narrowing code involving callables

Enhancements:

• Added performance optimization to better handle the case where a tuple expression contains thousands of entries. This is not typically found in hand-written code, but it can appear in computer-generated code.
• Added support for custom metaclasses that derive from ABCMeta. Classes instantiated from such metaclasses are now treated as abstract.
• Updated typeshed stubs to the latest version.

Behavior Changes:

• Changed the behavior of the dictionary expansion operator (**) when used in an argument expression for a call and the operand is a TypedDict. It now takes into account the fact that a (non-closed) TypedDict can contain additional keys with object values. This new behavior is consistent with mypy.
• Removed support for python-2 raise statements with comma-delimited operands.
• Changed behavior of raise evaluation logic to allow type of exception to be Never.
• Changed behavior to allow a value with type _AnnotatedAlias to be used with an implicit __getitem__ call even though this type is not documented or declared in typeshed.
• Changed stub generator to avoid emitting a from __future__ import statement, which has no meaning in stub files.
• Removed support for custom callable type guard pattern. Now that typeshed defines this with a TypeIs, we no longer require custom logic here.