Array prototype extensions fail circularly with `...args: T[]`, but not `args: T[]` about typescript HOT 6 OPEN

If there's some super straightforward fix here we can take it, but I wouldn't consider this a bug.

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It's not a crash. (I guess the template should explain what this means since so many people seem to choose this option erroneously.)

I'm not sure why this is supposed to be a bug; circularity warnings can be annoying but that doesn't rise to the level of a bug in the language. Yes, you can avoid warnings by changing your code. Note that the error message mentions that the problem is partially due to the lack of a type annotation on newMethods. So if I wanted to get your code working, I'd annotate like

const newMethods: {
    add<T>(this: T[], ...values: T[]): T;
} = {
    add(...values) { this.push(...values); return values[0]; }
};

Playground link

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I'm honestly confused why the code is written this way (interface Array<T> extends ...) instead of just augmenting Array directly. It's really weird to do declaration merging via extends, imo.

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It's not a crash. (I guess the template should explain what this means since so many people seem to choose this option erroneously.)

I'm not sure why this is supposed to be a bug; circularity warnings can be annoying but that doesn't rise to the level of a bug in the language. Yes, you can avoid warnings by changing your code. Note that the error message mentions that the problem is partially due to the lack of a type annotation on newMethods. So if I wanted to get your code working, I'd annotate like

const newMethods: {
    add<T>(this: T[], ...values: T[]): T;
} = {
    add(...values) { this.push(...values); return values[0]; }
};

Playground link

I created an issue as I feel the two examples should compile the same way, whether it's successful or unsuccessful. I can't see any reason why circular typing would invalidate one example but not the other - that is, I don't see why the spread operator would have any connection to circular type definitions.

Explicitly declaring the typing of newMethods introduces repetition and reduces maintainability - and everything works, without explicit typing, in the other example - why shouldn't it be able to work here? It feels like an inconsistency in typescript, and hence a bug (as opposed to feature request).

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#49263 (comment)

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I'm honestly confused why the code is written this way (interface Array<T> extends ...) instead of just augmenting Array directly. It's really weird to do declaration merging via extends, imo.

I think this way could allow for more maintainability if extending a prototype with many properties; extends automatically applies them without needing to manually enumerate the property names

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