Pyright

Behavior Change: Added code to disable the Pyright extension when the Pylance extension is installed. The two extensions are not intended to work together.

Bug Fix: Fixed bug in handling of specialized "tuple" class as defined in PEP 585.

Behavior Change: Changed the behavior of the command-line version of pyright when file specs are passed on the command line. Previously, file specs couldn't be used in conjunction with a config file. Now a config file is used, but the specified file specs override the "include" section of the config file.

Enhancement: Added validation of arguments passed to `__init_subclass__` method described in PEP 487.

Enhancement: Added detection of duplicate base classes in a class declaration.

Bug Fix: Fixed bug that generated incorrect "could not create consistent mro" error if one of the base classes was "Generic". The Python interpreter appears to special-case this class.

New Feature: Added support for new "reportWildcardImportFromLibrary" diagnostic rule that checks for the use of wildcard imports from non-local modules. By default, it is reported as a warning, but in strict mode it is an error.

Enhancement: Added code to synthesize custom overloaded "pop", "setdefault", and "__delitem__" methods for TypedDict classes.

Enhancement: Added support for the direct instantiation of a metaclass rather than using the normal metaclass hook.

Enhancement: Added support for PEP 585. Standard collection types defined in builtins can now be used like their typing counterparts. This includes "tuple", which needs special-case handling because its class definition in builtins.pyi indicates that it has a single type parameter, but it actually supports variadic parameters.

Bug Fix: Added code to prevent heap overrun errors during parsing/binding, most notably during indexing operations.

Bug Fix: Fixed bug that caused runtime crash if typeshed stubs couldn't be found or didn't define 'tuple'.

Bug Fix: Improved interaction between recursive type aliases and bidirectional type inference for lists and dicts.

Bug Fix: Improved type narrowing for assignments in cases where the destination of the assignment is declared as a union and the assigned type is a narrower form of one of the union elements. Previously, the narrowing logic didn't choose the narrowest type possible in this case.

Enhancement: Added perf optimization for unions that contain hundreds or thousands of int literal values. This is similar to another recent optimization for str literal unions.

From Pylance: Ensure that auto-import doesn't place import statement below usage.

Enhancement: Improved type analysis perf by about 5% and reduced memory usage slightly by not formatting and logging diagnostic messages in cases where they are suppressed (e.g. argument type mismatches when doing overload matching).

Bug Fix: Fixed bug that affected dependency tracking of source files on platforms with case-insensitive file systems. In some cases, the case of paths differed, and the logic was treating these as separate files.

Enhancement: Added diagnostics for type variables that are used improperly as defined in PEP 484: 1) conflicting type variables that are used in nested generic class declarations, and 2) type variables that are used within annotations outside of a context in which they have meaning.

New Feature: Added support for "higher-order" type variables. You can now pass a generic function as an argument to another generic function, and the type var solver can solve the type variables for both at the same time.

New Feature: Added support for recursive type aliases.

Behavior Change: Updated the default Python version from 3.8 to 3.9. This is used only if it is not otherwise configured and there is no Python environment from which to determine the version.

Enhancement: Added checks for usage of certain built-in types that are defined as generic in the typeshed stubs but generate runtime exceptions if subscripted on older versions of Python (prior to 3.9). Such types need to be enclosed in quotes when used in annotations.

Bug Fix: Fixed bug that caused the recently-added "discriminated field type narrowing" to be used in cases where it should not. This resulted in types being narrowed inappropriately when a field was typed as a union of literals.

Behavior Change: Changed command-line version to not print any non-JSON output when "--outputjson" option is used.

Behavior Change: Changed behavior when "useLibraryCodeForTypes" is set to "false". Previously, all ".py" library code was ignored in this case. Now, ".py" types are used for types if the package has an associated "py.typed" file as specified in PEP 561. Packages with no "py.typed" file will still be ignored if "useLibraryCodeForTypes" is "false".

Bug Fix: Fixed a couple of bugs that resulted in the hover text incorrectly identifying a symbol as a "type alias".

Behavior Change: Changed type inference logic to use "List", "Set", and "Dict" rather than "list", "set" and "dict" when inferring the type of a list, set or dict expression. These are aliases for the same underlying class, but the upper-case versions are more consistent with type annotations used within the code.

Bug Fix: Fixed "NoReturn" inference logic for async functions. This logic was previously flagging the code after a call to such a function as unreachable.

Enhancement: Improved parser to detect syntax errors involving unpack operator within a comprehension.

Enhancement: Changed import resolution logic to allow binaries (e.g. ".so" files) to satisfy local imports (within the package), not just third-party imports (within site-packages).

Enhancement: Extended bidirectional type inference (expected types) to list comprehensions.

New Feature: Added new diagnostic rule "reportPropertyTypeMismatch" that verifies that the type of the input parameter to a property's setter is assignable to the return type of the getter.

Bug Fix: Fixed bug that caused a crash in the type checker in cases where type arguments were not provided to a few special-case built-in classes.

Bug Fix: Fixed a bug in the handling of generics that involve constrained TypeVars. The TypeVar matching logic was sometimes inappropriately specializing the type using the first constrained type.

Bug Fix: Added special-case handling in type checker for callers who request the type of an expression that happens to be a name used in a call expression to designate a named parameter. This isn't really an expression, so the code wasn't handling it correctly, but callers (such as the hover provider and the new semantic token provider) were assuming that it was safe. This resulted in incorrect "X is not defined" diagnostics being logged.

Enhancement: Improved completion suggestion behavior when the insertion point is between an identifier and an empty index (e.g. "f[]") or in the presence of a missing right square bracket (e.g. "f.[").

Behavior Change: Changed diagnostic related to type argument count to be controlled by the "reportGeneralTypeIssues" diagnostic rule. It was previously always emitted as an error.

From Pylance: Fix progress reporter type, auto-import/symbol changes, worker thread updates, improve auto-import tooltips (977)

Enhancement: Updated typeshed stubs to the latest version.

Bug Fix: Eliminated incorrect error when "super()" was used in a class where one or more parent classes were of an unknown type.

Bug Fix: Changed the handling of old-style comment method annotations to accept an optional annotation for "self" and "cls" parameters.

Bug Fix: Changed handling of dataclass classes that derive from a class whose type is unknown. The synthesized constructor now allows any parameter list in this case.

Enhancement: Improved completion provider to distinguish properties from other methods.

Behavior Change: Changed heuristics for function return type inference so methods that raise a NotImplementedError and have no other return path have an inferred return type of Unknown rather than NoReturn. Such methods should be marked as abstract, but frequently they are not.

Behavior Change: Changed the behavior of the import resolution logic to fail an import resolution of a multi-part name (e.g. "a.b.c") if it can't be fully resolved. This could produce false positives in cases where third-party libraries are using dynamic tricks to manipulate their package namespace, but it will eliminate false negatives.

Bug Fix: Suppress the use of "Unnecessary" diagnostic hints (used to display variables and code blocks in gray) if the LSP client claims not to support this tag.

Enhancement: Added new "reportMissingTypeArgument" diagnostic rule and enabled it by default in "strict" mode. It generates a diagnostic when a generic class or generic type alias is used in an annotation with no type arguments provided.

Bug Fix: Fixed handling of scopes for nested classes. The previous logic allowed an inner class to access variables defined in an outer class, which is not permitted.

Enhancement: Added check for raise statements that take an exception class but the class constructor requires one or more arguments.

Bug Fix: Fixed bug in tokenizer that cause line numbers to be off when an invalid token occurred at the end of a line.

Bug Fix: Fixed a bug in the Pyright parser. It was not correctly following the Python grammar spec when parsing type annotations, so it generated syntax errors in some cases where that was inappropriate.

Enhancement: Added a check and a general type diagnostic for metaclass conflicts.

Bug Fix: Fixed bug in command-line version that caused an error to be reported when "useLibraryCodeForTypes" or "verboseOutput" was specified in the pyrightconfig.json file.

Enhancement: Added support for protocol matching where the protocol includes an overloaded method.

Enhancement: Improved diagnostic messages for function type mismatches.

Enhancement: Improved diagnostic messages for tuple matching and union assignments.

Enhancement: Changed nested diagnostic messages to use non-breaking spaces so indentations are visible within the VS Code "Problems" panel.

Bug Fix: Fixed bug in reportIncompatibleMethodOverride diagnostic check. The logic was checking for wider parameter types when it should have been checking for narrower.

Bug Fix: Fixed bug in method override validation code. It wasn't applying partial specialization of the base class, resulting in inappropriate errors in some cases.

Bug Fix: Fixed bug in the type evaluation of expressions with + or - operators and integer literal operands. These expressions should evaluate to a literal type, not an int.

Bug Fix: Fixed bug in parsing of f-strings that contain \N escape and a Unicode character name that includes a hyphen.

Bug Fix: Fixed bug in type evaluator that caused an incorrect error when a class decorator was used for a generic class.

Bug Fix: (From Pylance) Fixed performance problem related to file change events triggered by reads from site-packages.

Enhancement: Enabled support for PEP 613 (TypeAlias).

Bug Fix: Fixed bug that caused type aliases to get expanded in some contexts when they shouldn't.

Bug Fix: Fixed bug that caused "from .A import *" to work incorrectly when the wildcard included symbol A.

Enhancement: Added logic in completion provider to return class variables in base classes when the insertion point is in the context of a subclass body.

Bug Fix: Fixed TypeAlias code to check for Python 3.10 rather than 3.9 since PEP 613 has been moved out to 3.10.

Enhancement: Added performance optimization for TypedDict classes. Entries are now computed once and cached in the class type. This provides a big speed-up for TypeDict classes that have a large number of fields.

Enhancement: Added performance optimization for union types that contain large numbers of string literals. The code for inserting new items into a union is O(n^2); this optimization makes it O(n) for string literal types.

Bug Fix: Fixed bug that caused custom import aliases of "Final", "Literal" and "TypeAlias" to not work correctly.

Bug Fix: Fixed bug that resulted in spurious errors when hovering over module names in import statements.

Bug Fix: Fixed several bugs relating to symbols introduced into a class by its metaclass.

Bug Fix: Fixed bug that caused type analyzer to crash when a nonlocal binding referred to a symbol that was not present in an outer scope and then was assigned to.