Infer parametrized type of a callback argument based on the return value of the callback

[raven arch]

Any plausible way to infer the type of x in this snippet?
https://www.typescriptlang.org/play?#code/C4TwDgpgBAShwFcBOA7CSA8AVAfFAvFABQCU+OWAUJQGYIoDGwAlgPYpQ2uvY5E0oAXMQCGSAObC4iVOl5kKJAN7UAvtS6siRAB4KARAAtm+kgG5KUKwHprAPQD8QA

[mild sable]

@raven arch Here's a shortened URL of your playground link! You can remove the full link from your message.

hbtz#0

Playground Link

Preview:```ts
type Returner<T> = () => T

function foo<T>(fn: (arg: Returner<T>) => T) {}

foo(x => "hi")
//^?```

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[raven arch]

or, simpler:
https://www.typescriptlang.org/play?#code/GYVwdgxgLglg9mABMOcA8AVAfACmGALkRwEMAnAcyIwEoBeLWgbwCgWBfNlOHHAD3pYARAAsYQmgG4WiWQHo5APQD8QA