How to solve "Type instantiation is excessively deep and possibly infinite."

[young sail]

Explain the issue

I worked on a project for serialization and tried my best to strictly check the parameters passing from the user, so there's a deep check for nested data.
But the recursive check gives me the "Type instantiation is excessively deep and possibly infinite." error, and I have no idea how to solve this.

TypeScript Playground

https://shorturl.at/cgxU1

[limpid violet]

here's a reduced version of that problem to help you see what's going on:

[cold zephyr]

mkantor#0

Playground Link

Preview:```ts
type OptionType = {
option: Schema
}

type Schema = OptionType

type Nil = null | undefined

type Value<S extends Schema> = S extends OptionType
? Value<S["option"]> | Nil
: unknown

type Repro = Value<Schema>```

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[limpid violet]

unfortunately i have to run so can't help further right now, but hopefully that will help. if nobody else comes along after a while feel free to use the !helper command

[limpid violet]

i'm back and played around with your code a bit more. one way to avoid the infinite recursion issue is to introduce a self-imposed depth limit, like so:

https://tsplay.dev/mxql8W

there may be other/better approaches, that's just the first thing i tried that worked