vlib/v/checker/tests/map_option_key_err.vv:7:10: error: invalid key: cannot use `?string` as `string`, it must be unwrapped first
    5 |     mut c := cuid2.new()
    6 |     key := c.next()
    7 |     _ = m[c.next()]
      |             ~~~~~~
    8 |     m[c.next()] = 1
    9 |     m[key]++
vlib/v/checker/tests/map_option_key_err.vv:8:6: error: invalid key: cannot use `?string` as `string`, it must be unwrapped first
    6 |     key := c.next()
    7 |     _ = m[c.next()]
    8 |     m[c.next()] = 1
      |         ~~~~~~
    9 |     m[key]++
   10 | }
vlib/v/checker/tests/map_option_key_err.vv:9:4: error: invalid key: cannot use `?string` as `string`, it must be unwrapped first
    7 |     _ = m[c.next()]
    8 |     m[c.next()] = 1
    9 |     m[key]++
      |       ~~~
   10 | }