Add static index signature by Kingwl · Pull Request #37797 · microsoft/TypeScript (original) (raw)

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The implementation looks good, but I'd love to see some more tests (you should consider placing them in a subfolder of the conformance directory instead of compiler, since it's a "new" language feature). Specifically, I'm thinking of tests showing:

• Class static inheritance both inheriting and overriding index signatures (and issuing errors if you override with an incompatible type)
• Assignability of class static sides to one another when index signatures are in place (readonly and not readonly)
• Assignability between class static sides and equivalent interfaces describing them
• Assignability between class static sides with generic static index signatures (this likely requires defining classes within a closure with generic parameters) to have some sanity checks on the behavior of variance digests with these
• Some usages with indexed access types, eg (typeof Cls)[string]
• Some usages with keyof, eg keyof typeof Cls
• Some usages with homomorphic mapped types, eg Extract<typeof Cls, string>

More would also be welcome, ofc, if you can think of any other possible edge cases.