Yes, e.g. `const Token = struct { kind: Kind, otherStuff: ... }`, where Kind is an enum where one of the values is Kind.error. Then since switch is exhaustive, you can just pattern match on kind as you iterate over tokens to handle the error case at whatever syntactic context is most appropriate.

The nice side-effect about this approach is that rather than following the standard error flow of bailing early and unwinding stack, you can keep parsing and collecting errors as you go.