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After downcasting an array of structs, my Variables View window shows that all of the values in my struct have shifted "down" (will explain in a second). But when I print(structName), the values are fine. However, when I run an equality check on the struct, it once again behaves as though my values have shifted.

For example, I am trying to downcast Model A to ModelProtocol. var m = Model A and has the values id: "1234", name: "Cal". When I downcast, m now has the values id:"", name:"1234" .

After downcasting an array of structs, my Variables View window shows that all of the values in my struct have shifted "down" (will explain in a second). But when I print(structName), the values are fine. However, when I run an equality check on the struct, it once again behaves as though my values have shifted.

For example, I am trying to downcast Model A to ModelProtocol. var m = Model A and has the values id: "1234", name: "Cal". When I downcast, m now has the values id:"", name:"1234" .

Actual Example Below:

Models that I want to downcast:

struct PrivateSchoolModel: Decodable, SchoolProtocol 
 var id: String
 var name: String
 var city: String
 var state: String


struct PublicSchoolModel: Decodable, SchoolProtocol 
 var id: String
 var name: String
 var city: String
 var state: String 
 var latitude: String
 var longitude: String

Protocol I want to downcast to:

protocol SchoolProtocol 
 var id: String get set 
 var name: String get set 
 var city: String get set 
 var state: String get set 
 var longitude: Float get set 
 var latitude: Float get set 


extension SchoolProtocol 
 var longitude: Float 
 get return -1.0 
 set 
 
 var latitude: Float 
 get return -1.0 
 set 
 

Downcasting:

guard let downcastedArr = privateSchoolArray as? [SchoolProtocol] else return 

Result (item at index 0) or originalArr:

id = "1234"
name = "Leo High School"
city = "Bellview"
state = "WA"

Result (item at index 0) of downcastedArr:

id = ""
name = "1234"
city = "Leo High School"
state = "Bellview"

But if I print(downcastArr[0]), it will show:

id = "1234"
name = "Leo High School"
city = "Bellview"
state = "WA"

But if I try originalArray[0].id == downcastArr[0].id, it returns false

My Code with the problem:

class SchoolJSONHandler 
 private enum JSONFile: String 
 case publicSchool = "publicSchool"
 case privateSchool = "privateSchool"
 

 private lazy var privateSchoolArray = getPrivateSchools()
 private lazy var publicSchoolArray = getPublicSchools()

 func getSchoolArray(sorted: Bool, filtered: Bool, by stateAbbreviation: String?) -> [SchoolProtocol] 
 var schools = combineArrays()

 if sorted 
 schools.sort(by: $0.name < $1.name )
 

 if filtered 
 guard let abbr = stateAbbreviation else return 
 schools = schools.filter 
 return $0.state == abbr
 
 

 return schools
 

 private func combineArrays() -> [SchoolProtocol] 
 // EVERYTHING IS FINE IN NEXT LINE
 let a = privateSchoolArray
 // PROBLEM OCCURS IN NEXT 2 LINES WHEN DOWNCASTING
 let b = privateSchoolArray as [SchoolProtocol]
 let c = publicSchoolArray as [SchoolProtocol]
 return b + c
 

 private func getPublicSchools() -> [PublicSchoolModel] 
 guard let jsonData = getJSONData(from: .publicSchool) else return 
 guard let schools = decode(jsonData: jsonData, using: [PublicSchoolModel].self) else return 
 return schools
 

 private func getPrivateSchools() -> [PrivateSchoolModel] 
 guard let jsonData = getJSONData(from: .privateSchool) else return 
 guard let schools = decode(jsonData: jsonData, using: [PrivateSchoolModel].self) else return 
 return schools
 

 private func getJSONData(from resource: JSONFile) -> Data? 
 let url = Bundle.main.url(forResource: resource.rawValue, withExtension: "json")!
 do 
 let jsonData = try Data(contentsOf: url)

 return jsonData
 
 catch 
 print(error)
 

 return nil
 

 private func decode<M: Decodable>(jsonData: Data, using modelType: M.Type) -> M? 
 do 
 //here dataResponse received from a network request
 let decoder = JSONDecoder()
 let model = try decoder.decode(modelType, from:
 jsonData) //Decode JSON Response Data

 return model
 catch let parsingError 
 print("Error", parsingError)
 

 return nil
 

And then it is just called in another class by schoolJSONHandler.getSchoolArray(sorted: true, filtered: true, by: "WA")