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NonNullable doesn't work on mapped types instantiated with null/undefinedΒ #57151
Closed as not planned
Description
π Search Terms
mapped nonnullable empty object null undefined instantiation
π Version & Regression Information
- This changed in PR: Improve intersection reduction and CFA for truthy, equality, and typeof checksΒ #49119
β― Playground Link
π» Code
type Foo<T> = NonNullable<{ [K in keyof T]: T[K] }>
type Result = Foo<null>π Actual behavior
Result is of type null
π Expected behavior
Result should be of type never
Additional information about the issue
This likely gets closed as a design limitation like the one here: #56644
Activity
ahejlsberg commentedon Mar 6, 2024
That is indeed what I'm going to do. π
typescript-bot commentedon Mar 9, 2024
This issue has been marked as "Design Limitation" and has seen no recent activity. It has been automatically closed for house-keeping purposes.