(diagnostic
  (schema slovo.diagnostic)
  (version 1)
  (severity error)
  (code OptionObservationTypeMismatch)
  (message "`is_some` requires an `(option i32)`, `(option i64)`, `(option f64)`, `(option bool)`, or `(option string)` value")
  (file "<fixture>")
  (span
    (bytes 47 48)
    (range 5 12 5 13)
  )
  (expected "(option i32), (option i64), (option f64), (option bool), or (option string)")
  (found "i32")
)