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Fixed a bug in the type narrowing for the "x is <class>" type guard pattern when <class> is a specific class T, as opposed to a variable of type type[T]. This addresses #8264.

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This commit is contained in:
Eric Traut 2024-06-29 11:04:30 -07:00
parent fa0f6b7349
commit d55be983e5
2 changed files with 63 additions and 23 deletions
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66
packages/pyright-internal/src/analyzer/typeGuards.ts
View File

@ -2463,33 +2463,69 @@ function narrowTypeForClassComparison(
isPositiveTest: boolean
): Type {
return mapSubtypes(referenceType, (subtype) => {
const concreteSubtype = evaluator.makeTopLevelTypeVarsConcrete(subtype);
let concreteSubtype = evaluator.makeTopLevelTypeVarsConcrete(subtype);
if (isPositiveTest) {
if (isNoneInstance(concreteSubtype)) {
return undefined;
return isNoneTypeClass(classType) ? classType : undefined;
}
if (isClassInstance(concreteSubtype) && TypeBase.isInstance(subtype)) {
if (ClassType.isBuiltIn(concreteSubtype, 'type')) {
return classType;
if (
isClassInstance(concreteSubtype) &&
TypeBase.isInstance(subtype) &&
ClassType.isBuiltIn(concreteSubtype, 'type')
) {
concreteSubtype =
concreteSubtype.typeArguments && concreteSubtype.typeArguments.length > 0
? convertToInstantiable(concreteSubtype.typeArguments[0])
: UnknownType.create();
}
if (isAnyOrUnknown(concreteSubtype)) {
return classType;
}
if (isClass(concreteSubtype)) {
if (TypeBase.isInstance(concreteSubtype)) {
return ClassType.isBuiltIn(concreteSubtype, 'object') ? classType : undefined;
}
return undefined;
}
const isSuperType = isIsinstanceFilterSuperclass(
evaluator,
subtype,
concreteSubtype,
classType,
classType,
/* isInstanceCheck */ false
);
if (isInstantiableClass(concreteSubtype) && ClassType.isFinal(concreteSubtype)) {
if (
!ClassType.isSameGenericClass(concreteSubtype, classType) &&
!isIsinstanceFilterSuperclass(
if (!classType.includeSubclasses) {
// Handle the case where the LHS and RHS operands are specific
// classes, as opposed to types that represent classes and their
// subclasses.
if (!concreteSubtype.includeSubclasses) {
return ClassType.isSameGenericClass(concreteSubtype, classType) ? classType : undefined;
}
const isSubType = isIsinstanceFilterSubclass(
evaluator,
subtype,
concreteSubtype,
classType,
classType,
/* isInstanceCheck */ false
)
) {
);
if (isSuperType) {
return classType;
}
if (isSubType) {
return addConditionToType(classType, getTypeCondition(concreteSubtype));
}
return undefined;
}
if (ClassType.isFinal(concreteSubtype) && !isSuperType) {
return undefined;
}
}

20
packages/pyright-internal/src/tests/samples/typeNarrowingIsClass1.py
View File

@ -5,17 +5,14 @@ from typing import Any, TypeVar, final
@final
class A:
...
class A: ...
@final
class B:
...
class B: ...
class C:
...
class C: ...
def func1(x: type[A] | type[B] | None | int):
@ -34,7 +31,7 @@ def func2(x: type[A] | type[B] | None | int, y: type[A]):
def func3(x: type[A] | type[B] | Any):
if x is A:
reveal_type(x, expected_text="type[A] | Any")
reveal_type(x, expected_text="type[A]")
else:
reveal_type(x, expected_text="type[B] | Any")
@ -51,7 +48,7 @@ T = TypeVar("T")
def func5(x: type[A] | type[B] | type[T]) -> type[A] | type[B] | type[T]:
if x is A:
reveal_type(x, expected_text="type[A] | type[T@func5]")
reveal_type(x, expected_text="type[A] | type[A]*")
else:
reveal_type(x, expected_text="type[B] | type[T@func5]")
@ -63,3 +60,10 @@ def func6(x: type):
reveal_type(x, expected_text="type[str]")
else:
reveal_type(x, expected_text="type")
def func7(x: type[A | B]):
if x is A:
reveal_type(x, expected_text="type[A]")
else:
reveal_type(x, expected_text="type[B]")