"foo,bar,baz".split(1)

# output:
stdin:1:21
  ╷
1 │ "foo,bar,baz".split(1)
  ╵                     ^
Error: Separator must be a string.

stdin:1:20
  ╷
1 │ "foo,bar,baz".split(1)
  ╵                    ^
In call to method 'String.split'.