clarification needed to use with codable classes

[laimis17]

Let's say this encoder encodes class with inherintace and depends on default encode(to:) implementation. What i see is that it tries to encode superclass keys into keyed container as expected and then stops. Any ideas ?
Here's the test

func testClassWInheritance() {
class L1: Codable {
init() {
L1_A_KEY="AAAA"
L1_B_KEY=222
L1_D_KEY=4.4
}
var L1_A_KEY: String
var L1_B_KEY: Int
var L1_C_KEY: Int = 2
var L1_D_KEY: Float
private enum CodingKeys: String, CodingKey {
case L1_A_KEY
case L1_B_KEY
case L1_D_KEY
}
}

  class L2:L1 {
  	override init() {
  		L2_A_KEY="L2222"
  		L2_B_KEY=222333
  		L2_C_KEY=L3(L3_A_KEY: "L3333", L3_B_KEY: 333)
  		super.init()
  	}
  	
  	required init(from decoder: Decoder) throws {
  		fatalError("init(from:) has not been implemented")
  		try super.init(from: decoder)
  	}
  	var L2_A_KEY: String
  	var L2_B_KEY: Int
  	struct L3: Codable {
  		var L3_A_KEY: String
  		var L3_B_KEY: Int
  	}
  	var L2_C_KEY: L3
  }
  
  let t = L2()
  debugPrint(t)
  let encoder = MyEncoder()
  XCTAssertNoThrow( try encoder.encode(t))

}

(sorry, can't format to look readable. when editing all code formating is intact, but when saved, this happens)

debug result:

"creating keyed container"
"encoding L1_A_KEY"
"encoding L1_B_KEY"
"encoding L1_D_KEY"