Pyright

Bug Fix: Changed logic that detects generator functions to accommodate yield statements that are provably unreachable in the code flow.

Behavior Change: Changed dataclass logic to not enforce ordering of fields with defaults vs those without if `init=False` is specified.

Enhancement: Extended method override check to include dundered methods (other than constructors).

Bug Fix (from pylance): Removed duplicate "yield" suggestion in completion list.

Enhancement (from pylance): Improved logic that maps type stubs to corresponding source files.

Enhancement: Added support for implicit `__annotations__` symbol at the module level.

Enhancement: Updated to the latest typeshed stubs. Removed third-party stubs for that were marked as Python 2 only (enum34, fb303, futures, ipaddress, kazoo, openssl-python, pathlib2, pymssql, Routes, scribe, tornado).

Enhancement: Added support for `type(None)` within isinstance type narrowing.

Bug Fix: When providing a completion suggestion for an async method override, an "await" operator is now added in the generated return expression.

Bug Fix: Fixed false positive error in argument/parameter matching logic for function calls that occurs when a keyword argument targets a parameter that can be either positional or keyword and a spread operator is used in an earlier argument.

Bug Fix: Fixed bug that resulted in false positive error when a constrained TypeVar type was passed through the "isinstance" type narrowing logic and then used as an operand in a binary operation.

Bug Fix: Fixed several bugs that caused type checker crash in certain cases.

Bug Fix: Fixed bug in type narrowing logic when the narrowed expression contained an assignment expression (walrus operator). It was not properly narrowing the target of the assignment expression.

Bug Fix: Fixed bug in "isinstance" type narrowing support when the first argument is a type (e.g. a class or Type[T]) and the second argument is `type` (or a tuple that contains `type`).

Bug Fix: Fixed bug in "isinstance" type narrowing logic where it didn't properly handle protocol classes that support runtime checking.

Enhancement (from Pylance): Improved docstring formatting in hover text.

Behavior Change: Suppressed "access to non-required key" diagnostic if the access is performed within a try block.

Bug Fix: Fixed bug in 'callable' type narrowing logic. It wasn't properly handling type variables.

Enhancement: Implemented new diagnostic rule "reportUnnecessaryComparison". It checks for "==" and "!=" comparisons where the LHS and RHS types have no overlap and the LHS has no `__eq__` overload. This new diagnostic rule is off by default in normal type checking mode but is on in strict mode.

Bug Fix: Fixed false positive error that occurred when file started with "from typing import Collection". This was due to mishandling of a cyclical dependency in the typeshed classes.

Enhancement: Improved bidirectional type inference for expressions that involve the pattern `[<list elements>] * <expression>`.

Bug Fix: Fixed false positive error relating to the use of parentheses in "with" statement when using Python 3.9.

Bug Fix: Fixed bug in type evaluation of async functions that are not generators but have a declared return type of AsyncGenerator. The actual return type needs to be wrapped in a Coroutine in this case.

Bug Fix: Suppressed diagnostic check for `Subscript for class "X" will generate runtime exception` when it's used in a PEP 526-style variable type annotation. Apparently the exception occurs only when used in other contexts like parameter and return type annotations.

Enhancement: Added configuration option "strictSetInference" which is analogous to "strictListInference" and "strictDictionaryInference" but specifically for set expressions.

Enhancement: Tweaked heuristic in constraint solver to prefer types that have no "unknown" element to those that do.

Enhancement: Improved the handling of TypeVar matching when the source and dest types are both unions, the types are being compared with invariant constraints, and the dest contains a TypeVar.

Enhancement: Fixed misleading error message for "unsupported `__all__` operations".

Enhancement: Improved error message for dataclass fields.

Bug Fix: Fixed bug that caused inconsistent type evaluation for type annotations based on order of evaluation. It was triggered in some cases by the semantic highlighting feature.

Bug Fix: Fixed bug in the function type compatibility logic. If the source has a `*args` or `**kwargs` parameter but the dest does not, the function should still be assignable.

Behavior Change: Changed the logic that searches for a config file. It currently searches from the current working directory all the way up the folder hierarchy. This makes sense only for a command-line tool, not for a language server. The latter already knows the project root, and we should look only in that directory for a config file.

Bug Fix: Fixed bug in signature help provider where its heuristics were causing it to return a bad response when the insertion point was immediately after a comma and a call expression preceded the comma.

Bug Fix: Added support for an import edge case where a module's `__init__.py` file is apparently importing from itself but intends instead to import from one of its submodules.

Bug Fix: Fixed bug in namespace import resolution. When there are multiple import search matches, the import resolver needs to take into account the individual symbols specified in the import statement.

Bug Fix: Fixed a bug whereby call expressions within a type annotation were flagged as errors but not evaluated, which meant that symbols referenced within them were not marked as accessed.

Enhancement: Updated typeshed stubs to the latest.

Bug Fix: Fixed bug in argument-matching code that produced false positive errors when a keyword argument corresponded to a positional-only argument name but should have been matched to a **kwargs parameter instead.

Bug Fix: Fixed bug in bidirectional type inference logic for list and dict expressions when expected type included a type varaible.

Bug Fix: Disabled the "self" annotation checks for overloaded methods because the self annotation can be used as a legitimate filter for overloads.

Enhancement: Improved bidirectional type inference for set expressions so it better handles unions in expected type.

Bug Fix: Improved TypeVar constraint solver so it provides a better solution when a TypeVar is constrained first by a contravariant wide bound in a first argument and then a subsequent argument relies on bidirectional type inference with a covariant or invariant use of the same TypeVar.

Bug Fix: Fixed bug that caused a crash in the type checker when a protocol class inherited from a generic non-protocol class.

Enhancement: Added check for a class that inherits from Generic to ensure that all type variables are included in the Generic subscript list.

Bug Fix: Fixed regression in handling expressions of the form `[x] * y`. Some previously-added special-case code to handle the `[None] * n` case was too general.

Enhancement: Changed printed types to fully expand type aliases in error messages where that additional detail is needed — namely, for "partially unknown" messages. This makes for verbose types, but without the expansion, it can be very difficult to determine which part of the type is unknown.

Bug Fix: Fixed false positive error in type compatibility check where the destination type is `Type[Any]` and the source type is `Type[x]` where x is anything (including `Any`).

Enhancement: Added exemption to the overlapping overload check for the `__get__` method. Other type checkers (namely mypy) exempt this method also.

Bug Fix: Fixed bug in type evaluator that resulted in suppressed errors and evaluations when the evaluation of a lambda expression resulted in some form of recursion (e.g. it references a symbol that depends on the return result of the lambda).

Enhancement: Added "reportTypedDictNotRequiredAccess" diagnostic rule and split out diagnostics that pertain specifically to unguarded accesses to non-required TypedDict keys.

Bug Fix: Changed type of `__path__` variable in module from `List[str]` to `Iterable[str]`.

Bug Fix: Fixed bug that resulted in a runtime crash within the type checker when a protocol class inherits from another protocol class that is not generic (like "Sized").

Enhancement: Added better heuristics to auto-complete insertion logic so it honors single-symbol-per-line and multi-symbol-per-line formats of "from x import a" statements.

Enhancement: Implemented a new check to validate that annotated types for "self" and "cls" parameters are supertypes of their containing classes.

Bug Fix (from pylance): Fixed bug that resulted in crashes when a broken symlink was encountered.

Bug Fix: Fixed recent regression that resulted in false positives when checking the type of a "self" parameter within a metaclass when the type annotation was of the form `Type[T]`.

Enhancement: Added minimal support for "no_type_check" decorator. It does not suppress errors, but it doesn't generate an error itself.

Enhancement: Added support for PEP 612 ParamSpecs to be used as type parameters for generic classes and generic type aliases. Previously, they were allowed only in the specialization of `Callable`.

Enhancement: Added out-of-bounds access check for index operations where the indexed type is a tuple object with known length and the index value is a negative integer literal value.

Bug Fix: Fixed bugs in the handling of PEP 487 `__init_subclass__`. The logic was using the `__init_subclass__` defined in the class itself rather than its base classes.

Enhancement: Added special-case handling for generic functions that return a `Callable` with generic parameters. The change allows for callers to pass type variables to the function and then have the resulting `Callable` provide a TypeVar scope for those variables.

Bug Fix (from pylance): Fixed bugs relating to partial type stub packages.

Bug Fix: Fixed bug that affected the use of the `tuple` constructor. It was not properly updating the variadic type arguments. This resulted in false negatives for the resulting type.

Bug Fix: Fixed bug that resulted in false negatives because diagnostics generated while analyzing a constructor call were suppressed.

Enhancement: Improved stub generator to print "x = ..." rather than include the RHS expression if `x` is not a type alias.

Enhancement: Added special-case handling for assignments of the form `x: List[A] = [a] * y` (the multiply operator on a list). This specific idiom is commonly used to initialize a list with None values.

Performance: Added perf improvements that help when dealing with unions that contain many tuples. Improved TypeVar constraint solver to better handle the case where a type is widened to include hundreds of subtypes, thus grinding performance to a halt. This occurs in one of the modules in pytorch.

Enhancement: Rewrote package type verifier based on feedback from users. Its error messages are now much clearer, it distinguishes between "exported symbols" and "other referenced symbols", it properly handles properties, and it omits warnings about missing docstrings by default (can be overridden with "--verbose" setting).

Bug Fix: Fixed bug that resulted in incorrect type evaluation for a constructor call when the class's `__new__` method returns an instance of a different class.