Fix excess property checking for nullary sums #4
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| // It should be noted that excess property checking won't help us if the input | ||
| // object is first defined elsewhere and then provided to our function. This | ||
| // should be considered an unsafe, unsupported use of this API. |
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Correct, it just seemed worth writing down.
| return ( | ||
| eq === undefined || | ||
| // eslint-disable-next-line @typescript-eslint/no-explicit-any | ||
| (eq as unknown as Eq<Value<A>>).equals(xv as any, yv as any) |
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Do you know how eq gets its type const eq: Eqs<A>[keyof Eqs<A>] & ({} | null) after the equality test with undefined while it was simply const eq: Eqs<A>[keyof Eqs<A>] before it?
I'm trying to understand what makes the type assertion necessary; I don't exactly understand how eq can be inferred as anything other than Eq<Value<A>>.
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I'm not seeing that inferred intersection. I wouldn't waste much time on it though, these libraries are all absolutely littered with assertions. I don't think there's much we can do about it (though you're welcome to try 😉). The only real concern for me is what's consumer-facing.
Fixes #3 with only type-level changes.