// error in non-mut as receover struct Box { mut: value int } fn (mut box Box) set(value int) { box.value = value } fn non_mut_receiver() { Box{}.set(0) } // error in array chained method calls fn array_chained_method_calls() { path := 'hello/file.txt' _ = path.split('.').pop() } // error in map chained method calls fn map_chained_method_calls() { mut m := map[int]int{} m.clone().delete(0) }