selfを参照するclosureメンバg（参照：http://stackoverflow.com/questions/29366270/closure-use-unresolved-identifier-self）

unresolved_self.swift

class Bar {
  let someVal = 5
  lazy var g:() -> String =  { [unowned self] in
// lazy: 次のエラー対策：error: use of unresolved identifier 'self'
    return String(self.someVal)
  }
}
var bar = Bar()
print(bar.g()) // string "5"