Pyright

Bug Fix: Fixed a bug in isinstance type narrowing logic where the type of the second argument to isinstance is type `Type[T]` and the first argument is a union of types that includes type `T`.

Enhancement: Expanded reportUnusedCallResult diagnostic check to also check for expressions of the form await <call expression>.

Bug Fix (from Pylance): Changed language server to set the working directory before attempting to execute script to retrieve sys.paths.

Behavior Change (from Pylance): Separated behavior of "go to definition" and "got to declaration". The former tries to take you to the source, whereas the latter takes you to the stub file.

Bug Fix: Changed binding logic to not assume that an assignment to a simple name can generate an exception. This fixes a reported false positive error in a type narrowing case.

Enhancement: Added proper error check for the use of an unpack operator (*) when used outside of a tuple.

Bug Fix: Avoid generating a diagnostic for reporUnknownMemberType if the member access expression is used as a call argument and is a generic class that is missing type arguments. This case was already special-cased for reportUnknownArgumentType to handle common cases like `isinstance(x, list)`, but it was resulting in errors for `isinstance(x, re.Pattern)`.

Bug Fix: Fixed a hole in the detection of unspecified type arguments for the Tuple and tuple classes.

Enhancement: Added support for generic classes that are parameterized by ParamSpecs, as allowed in PEP 612.

Enhancement: Added some performance optimizations to handle cases where there are many overloads for a function (>100). Previous code hit n^2 analysis times where n is number of overloads.

Enhancement: Added perf optimization that avoids reallocation of special form classes (like Protocol and Literal) every time they're used. Since instance of the type is now cached and reused.

Enhancement (from Pylance): Improved formatting of docstrings in hover text, completion suggestions, and signature help.

Enhancement (from Pylance): Added better performance metrics.

Bug Fix (from Pylance): Improved logic to ignore temp files created by code formatters like black.

Bug Fix: Fixed "possibly unbound" false positive error in try/except/else/finally statement in the special case where a "bare except" clause is used.

Bug Fix: Replaced logic that detects whether a function's inferred type is "NoReturn" — and specifically whether its implementation is a "raise NotImplementedError". The old logic depended results that varied depending on the order in which types were evaluated and was therefore nondeterministic.

Bug Fix: Fixed false negative where type expressions used as arguments to TypedDict or NamedTuple constructors are not correctly checked for incompatibility with older versions of Python when they contain `|` or use PEP 585 types.

Behavior Change: Changed PEP 585 violations (e.g. using `list[int]` rather than `List[int]`) to be unconditional errors rather than diagnostics controlled by reportGeneralTypeIssues diagnostic rule. That way, they appear even when type checking is disabled.

Bug Fix: Reverted recent change in for/else statement logic because it introduced a regression.

Behavior Change: Changed the `reportUnboundVariable` default severity from "warning" to "none" when typeCheckingMode is "off". There were too many complaints of false positives from users who have no interest in type checking.

Enhancement: When a redundant form of a from .. import statement is used (e.g. `from x import foo as foo`), always mark the imported symbol as accessed because it is assumed that it is being re-exported.

Bug Fix: Fixed bug that caused incorrect type evaluation when a return type in a generic function used a Callable with Concatenate and a ParamSpec.

Bug Fix: Fixed bug in code that prints types (e.g. in error messages and hover text) that resulted in duplicate types in a union when typeCheckingMode was "off".

Enhancement: Updated code that prints function types (e.g. for error messages and hover text) to include unioned return types in parentheses to distinguish between `() -> (int | str)` and `() -> int | str`.

Bug Fix: Fixed formatting of usage text in CLI. Fix contributed by fannheyward.

Bug Fix: Fixed bug that caused problems when the type `ellipsis` was used in a type stub instead of `...`.

Bug Fix: Fixed recent regression in handling of isinstance second parameter.

Behavior change: Changed type inference logic for binary expressions of the form `x or []` so `[]` uses the type of `x` to inform its type.

Bug Fix: Fixed bug in the way a specialized variadic type alias is printed (for error messages, hover text, etc.).

Enhancement: Added support for subscript index lists that contain a trailing comma (e.g. `a[0,]`). The subscript in this case is a tuple and is not valid for most objects, so it should generate an error.

Enhancement: Improved parse error recovery for empty subscripts (e.g. `a[]`). Started to add support for PEP 637.

Enhancement: Improved consistency of error messages.

New Feature: Added support for PEP 637 (keyword and unpacked arguments in subscripts). This PEP is still in the draft phase and may change before being finalized.

New Feature: Added a way for the "verifytypes" feature to ignore partially-unknown types imported from external packages. To use this feature, append a "!" to the end of the package name provided after the "--verifytypes" option.

Bug Fix: Fixed cyclical type resolution with TypeVar.

Behavior Change: Updated typeshed stubs to new directory layout.

Bug Fix: Fixed false positive error in try/except/finally statement. Call expressions are now assumed to possibly result in raised exceptions, and finally clauses are assumed to be exception targets.

Bug Fix: Fixed regression in import resolution where the first portion of the import path matches multiple namespace packages.

New Feature: Added initial support for PEP 646 (variadic type variables). This PEP is still in the draft stage and is likely to change before it is ratified.

Enhancement: Added check for duplicate keyword arguments that map to **kwargs parameter.

Enhancement: Added support for class properties, which are now supported in Python 3.9.

Behavior: Eliminated false positive errors for unbound variables that are targets of a for loop iterator and used after the for loop. This change can result in some false negatives.

Bug Fix: Added missing check for empty f-string expression.

Bug Fix: Fixed a bug that resulted in incorrect bidirectional type inference when the source was a call to a constructor and the destination (expected) type was a recursive type alias that includes a union with only some subtypes that match the constructed type.

Bug Fix: Fixed two issues in the import resolution logic. First, it was returning a namespace module if it found one in the workspace path or extraPaths even if a traditional (non-namespace) module satisfied the import from the sys.path. The interpreter searches all paths and always prefers a traditional module if it can find it. Second, it was resolving a namespace module if a traditional module only partially resolved the import path. The real interpreter always prefers a traditional module even if it partially resolves the path (in which case the full import fails).

Behavior Change: When too few type arguments are provided for a generic class specialization, this diagnostic is now handled via reportGeneralTypeIssues rather than reportMissingTypeArgument. The latter is reserved for cases where type arguments are omitted completely.

Enhancement: Improved type narrowing logic for isinstance and issubclass so they better handle the case where the class passed in the second argument is a type variable.

Enhancement: Added missing check for ** used in argument expressions. The expression after the ** must be a mapping with str keys.

Enhancement: Added missing check for a name-only parameter appearing in a signature after a "*args: P.args" ParamSpec parameter.

Enhancement: Improved error message for non-keyword parameter that follows a "*" parameter.

Enhancement: Added missing check for positional argument count when a simple positional argument appears after a *args argument.

Enhancement: Added missing checks for illegal usage of positional parameters when calling a function defined with ParamSpec and Concatenate.

Enhancement: Added missing check for use of keyword arguments in a call to an inner function that uses P.args and P.kwargs defined by a ParamSpec.

Bug Fix: Fixed false positive warning relating to single use of a type variable within a signature when that type variable is a ParamSpec, and it is also referenced in "P.args" or "P.kwargs" annotations.

Enhancement: Added missing PEP 612 support for functions that take a parameter with a callable type that includes a ParamSpec as well as *args: P.args and **kwargs: P.kwargs parameters.

Bug Fix: Fixed false positive error related to use of "ClassVar" when it is used in a member access expression like "typing.ClassVar".

Enhancement: Improved performance for deeply nested expressions that involve calls to overloaded functions.

Bug Fix: Fixed crash when "()" is used as a type argument for a class that doesn't accept variadic type parameters.