(diagnostic
  (schema slovo.diagnostic)
  (version 1)
  (severity error)
  (code ArityMismatch)
  (message "function `std.vec.i64.len` called with wrong number of arguments")
  (file "<fixture>")
  (span
    (bytes 37 54)
    (range 5 3 5 20)
  )
  (expected "1")
  (found "0")
)