Error Lab

Every diagnostic below is the real output of ptc, not a mock-up. Pick a mistake, read how the compiler teaches the canonical form, then flip to the fix.

let opt: Option[Int] = Some(1)
match opt:
    case Some(n):
        print("{n}")

error: this match on Option[Int] is not exhaustive — cover both 'case Some(...):' and 'case None:' or finish with a 'case _:' arm (line 2, column 1)

let opt: Option[Int] = Some(1)
match opt:
    case Some(n):
        print("{n}")
    case None:
        print("none")

1