vlib/v/checker/tests/unimplemented_interface_b.vv:13:6: error: `Cat` incorrectly implements method `name` of interface `Animal`: expected return type `string`
   11 | fn main() {
   12 |     c := Cat{}
   13 |     foo(c)
      |         ^
   14 | }
Details: main.Animal has `fn name(x main.Animal) string`
         main.Cat has `fn name(c main.Cat)`