Improve assignability to target conditional types types that distribute with any/unknown extendsType
#60817
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…te with any/unknown `extendsType`
typescript-bot
added
the
For Uncommitted Bug
Andarist
commented
Dec 19, 2024
| @@ -19321,7 +19321,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker { | |||
| } | |||
|
|
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| function isDistributionDependent(root: ConditionalRoot) { | |||
| return root.isDistributive && ( | |||
| return root.isDistributive && !(root.extendsType.flags & TypeFlags.AnyOrUnknown) && ( | |||
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This isn't correct as it removes those correct errors:
function f5<T>(t1: { x: T; y: T }, t2: T extends any ? { x: T; y: T } : never) {
t1 = t2; // OK
t2 = t1; // should fail
}
function f6<T>(t1: { x: T; y: T }, t2: T extends unknown ? { x: T; y: T } : never) {
t1 = t2; // OK
t2 = t1; // should fail
}
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fixes #60815