vlib/v/checker/tests/array_of_refs_insert_non_ref.vv:16:12: error: cannot append `Dummy` to `[]&Dummy`
   14 |         v: 1
   15 |     }
   16 |     c.vals << d
      |               ^
   17 |     c.vals.insert(0, d)
   18 | }
vlib/v/checker/tests/array_of_refs_insert_non_ref.vv:17:19: error: cannot insert `Dummy` to `[]&Dummy`
   15 |     }
   16 |     c.vals << d
   17 |     c.vals.insert(0, d)
      |                      ^
   18 | }