Excessive Stack Depth from DeepPartial/RecursivePartial in 2.7.x

[kevinbeal]

Search Terms:
"excessive depth"
"generic partial"

Code

const fn = <T>(arg: T) => {
    ((arg2: RecursivePartial<T>) => {
        // ...
    })(arg); // <-- here
};

type RecursivePartial<T> = {
    [P in keyof T]?: RecursivePartial<T[P]>;
};

Expected behavior:
Comparing a generic with a partial of that generic working without errors.

Actual behavior:
Getting "Excessive stack depth comparing types 'T' and 'RecursivePartial'." since upgrading to 2.7.x. (Also errors in 2.8.x). Working in 2.6.1.

Playground Link:
https://www.typescriptlang.org/play/index.html#src=class%20Greeter%20%7B%0D%0A%20%20%20%20greeting%3A%20RecursivePartial%3Cstring%3E%3B%0D%0A%20%20%20%20constructor(message%3A%20string)%20%7B%0D%0A%20%20%20%20%20%20%20%20this.greeting%20%3D%20message%3B%0D%0A%20%20%20%20%7D%0D%0A%20%20%20%20greet()%20%7B%0D%0A%20%20%20%20%20%20%20%20return%20%22Hello%2C%20%22%20%2B%20this.greeting%3B%0D%0A%20%20%20%20%7D%0D%0A%7D%0D%0A%0D%0Alet%20greeter%20%3D%20new%20Greeter(%22world%22)%3B%0D%0A%0D%0Alet%20button%20%3D%20document.createElement('button')%3B%0D%0Abutton.textContent%20%3D%20%22Say%20Hello%22%3B%0D%0Abutton.onclick%20%3D%20function()%20%7B%0D%0A%20%20%20%20alert(greeter.greet())%3B%0D%0A%7D%0D%0A%0D%0Adocument.body.appendChild(button)%3B%0D%0A%0D%0Aconst%20fn%20%3D%20%3CT%3E(arg%3A%20T)%20%3D%3E%20%7B%0D%0A%20%20%20%20((arg2%3A%20RecursivePartial%3CT%3E)%20%3D%3E%20%7B%0D%0A%20%20%20%20%20%20%20%20%2F%2F%0D%0A%20%20%20%20%7D)(arg)%3B%0D%0A%7D%3B%0D%0A%0D%0Atype%20RecursivePartial%3CT%3E%20%3D%20%7B%0D%0A%20%20%20%20%5BP%20in%20keyof%20T%5D%3F%3A%20RecursivePartial%3CT%5BP%5D%3E%3B%0D%0A%7D%3B

Related Issues:
None?

[Conaclos]

I got the same code with the next code:

type SafeAny <T> = {
    [k in keyof T]?: SafeAny<T[k]>
} | boolean | number | string | symbol | null | undefined

type DataValidator <T> = {
    [k in keyof T]?: (v: SafeAny<T[k]>) => v is T[k]
}

The following error is reported:

error TS2321: Excessive stack depth comparing types 'T[k]' and 'SafeAny<T[k]>'.

@kevinbeal
Your playground link is wrong (you need to hit "share" before copying the link).

[kevinbeal]

@Conaclos In what sense exactly is the link wrong? I did hit "share". It wouldn't be a really long URL with url encoded typescript in the URL if I hadn't. Are you not seeing the issue when you click the link?

[Conaclos]

@kevinbeal
Sorry, I expected the same code than the one posted here...

[sandersn]

From bisecting, the bad commit is part of #19564.