All,
I have encountered a misleading error message that kept me in debugging for a few minutes until I actually realized what's the problem.
I have simplified it down to this:
import Foundation
struct S {
var foo: Int
var bar: String
}
extension S: Decodable {
enum CodingKeys: String, CodingKey {
case foo, bar
}
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
foo = try container.decode(Int.self, forKey: .foo)
let tmpBar = try container.decode(String.self, forKey: .bar)
bar = tmpBar.map({ (char) -> String in
// ^--- `bar` captured by closure error here
return "\(char)\(foo)"
}).joined(separator: " ")
}
}
The problem is that I'm decoding a .bar keyed value into temporary variable tmpBar that I'm later using to derive a real bar value. And I used foo instance variable to do that. However the error message tells me that bar was actually captured by a closure before being initialised. To fix I just had to do a local copy of instance variable that I was using inside map closure.
So I just wonder if this is the intended behavior.