mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-29 07:04:09 +08:00
Chris Tate
3ef34770bd
`a?.[i]` on a binding whose type admits undefined, such as a `string[] | undefined` parameter, threw "undefined is not representable in the target union" when the binding held undefined. Element access replaced an identifier receiver whose storage has an undefined arm with a checked narrow to its present arm before the optional chain ran, so the chain saw a receiver that is never nullish and lowered `?.[` as a plain element read. Element access now leaves the receiver to the optional chain when the access carries `?.`; the chain tests the undefined arm and lowers the access again inside its guard. This applies to arrays, tuples and record keys. Property access (`a?.length`, `a?.at(0)`) already lowered through the chain. Corpus 8330 matches Node's output.