package main import ( "fmt" "errors" ) type Int int type Person struct { Name string Surname string } func (p Person) String() string { return fmt.Sprintf("%s\n%s", p.Name, p.Surname) } func (i Int) Inc() Int { i++ return i } func Foo(i int) (int, error) { if i > 0 { return 0, errors.New("FUCK YOU") } return -i, nil }