" Duplicate keys of type ... were found in a Dictionary " when there is no Dictionary?

Question

I'm quite new to Swift and I just encountered an error I don't find a solution for. I'm currently working on a game (Boggle, for the curious) and I want to update the list of words that the algorithm has found.

I created a struct to hold each word and the points it scores :

struct ScoredWord: Comparable, Identifiable{
let word: String
var points: Int = 0
let id: UUID

init(word: String){
    self.id = UUID()
    self.word = word
    self.points = self.defineScore(word: word)
}

static func < (lhs: ScoredWord, rhs: ScoredWord) -> Bool {}

static func == (lhs: ScoredWord, rhs: ScoredWord) -> Bool {}

func hash(into hasher: inout Hasher) {

private func defineScore(word: String) -> Int{}

(I removed the content of the func for it's useless to you)

Once the algorithm is done, I have simple loop that created a struct for each word found and stores it in the array that is @Published for display

let foundWords = solver.findValidWords()
    
for found in foundWords {
    wordList.append(ScoredWord(word: found))
}

The array is used in my view this way:

 List(wordListViewModel.wordList, id: \.self) { // 1 Word list
     Text( $0.word )
     Spacer()
     Text("\( $0.points )")
 }

The error I get when I run all of this is:

Fatal error: Duplicate keys of type 'ScoredWord' were found in a Dictionary. 
This usually means either that the type violates Hashable's requirements, or
that members of such a dictionary were mutated after insertion.

I found this post about the same error where a comment states that the error would come from the list not being displayed fast enough and id getting mixed up, but nothing about how to fix it...

Any idea?

Answer 1

I think you are missing a full conformance to the Hashable Protocol

Pay attention to the func hash(into hasher: inout Hasher) function which you are missing

Answer 2

Hash table is a dictionary. What is the true difference between a dictionary and a hash table?

It appears that some structs in your array are made using identical words & points. Add another variable to your struct:

var identifier = UUID()

It will generate a unique ID.