(diagnostic
  (schema slovo.diagnostic)
  (version 1)
  (severity error)
  (code IfConditionNotBool)
  (message "`if` condition must be bool")
  (file "<fixture>")
  (span
    (bytes 41 76)
    (range 5 7 5 42)
  )
  (expected "bool")
  (found "(result f64 i32)")
)