Closure cannot implicitly capture self parameter. Swift

Question

I've got an error "Closure cannot implicitly capture self parameter". Tell me please how it fix?

struct RepoJson {
...
    static func get(url: String, completion: @escaping (RepoJson!) -> ()) {
        ...
    }
} 

struct UsersJson {
    var repo: RepoJson!
    init() throws {   
        RepoJson.get(url: rep["url"] as! String) { (results:RepoJson?) in
            self.repo = results //error here
        }
   }
}

Answer 1

It's because you're using struct. Since structs are value, they are copied (with COW-CopyOnWrite) inside the closure for your usage. It's obvious now that copied properties are copied by "let" hence you can not change them. If you want to change local variables with callback you have to use class. And beware to capture self weakly ([weak self] in) to avoid retain-cycles.