(diagnostic
  (schema slovo.diagnostic)
  (version 1)
  (severity error)
  (code DuplicateMatchArm)
  (message "duplicate `some` match arm")
  (file "<fixture>")
  (span
    (bytes 110 122)
    (range 8 6 8 18)
  )
  (related
    (span
      (file "<fixture>")
      (bytes 75 89)
      (range 6 6 6 20)
      (message "original match arm")
    )
  )
)