vlib/v/checker/tests/function_cast_outside_unsafe_err.vv:6:10: error: casting a function value from one function signature, to another function signature, should be done inside `unsafe{}` blocks
    4 | fn main(){
    5 |     f := fn(){}
    6 |     println(FnB(f))  // not FnA()
      |             ~~~~~~
    7 | }
