Function allows me to build invalid partial

[f-g-p]

Hello,

I have the following piece of code that allows me to produce an invalid partial object:

type A = { a: number; b: string };

const buildPartial = (key: keyof A, val: A[keyof A]): Partial<A> => ({ [key]: val });
const test = buildPartial('a', 'hello'); // allows me to build an invalid object without compile error

Shouldn't I have a compile error? { [key]: val } seems to of type { a: number | string } | { b: number | string } which is not compatible with Partial
Thanks
ps: I understand I should have written const buildPartial = <K extends keyof A>(key: K, val: A[K]) => ... My question is not on this, it is on why this was not caught by the compiler

[jcalz]

Looks like you used the wrong template to file a bug report.

Caused by #13948 making an index signature and maybe #27144 not checking against the weak type... so this probably is indeed a duplicate, not that you intended to file it as one.

[typescript-bot]

This issue has been marked as "Duplicate" and has seen no recent activity. It has been automatically closed for house-keeping purposes.