Optional ReadonlyoffsetByte or character offset where the problem was detected, when known.
Optional ReadonlycauseUnderlying structured cause, when a parser layers errors.
ReadonlykindStable machine-readable discriminator.
ReadonlymessageHuman-readable error message.
Optional ReadonlytokenIndex where the logical token started.
Optional ReadonlyerrorIndex where the error was detected.
Structured parser error with both token and error positions when known.