when elem is
            UnknownStrategy _ -> state
            RockVsRockDraw score -> state + score
            RockVsPaperWin score -> state + score
            RockVsScissorsLoss score -> state + score
            PaperVsRockLoss score -> state + score
            PaperVsPaperDraw score -> state + score
            PaperVsScissorsWin score -> state + score
            ScissorsVsRockWin score -> state + score
            ScissorsVsPaperLoss score -> state + score
            ScissorsVsScissorsDraw score -> state + score

when elem is
    UnknownStrategy _ -> state
     _ score -> state + score

── MISSING ARROW ──────────────────────────────────────────────────── main.roc ─

I am partway through parsing a when expression, but got stuck here:

65│          when elem is
66│              UnknownStrategy _ -> state
67│              _ score -> state + score
                   ^

I was expecting to see an arrow next.

Note: Sometimes I get confused by indentation, so try to make your when
look something like this:

    when List.first plants is
      Ok n ->
        n

      Err _ ->
        200

Notice the indentation. All patterns are aligned, and each branch is
indented a bit more than the corresponding pattern. That is important!%