I have this code

  let firstRow = ["q", "w", "e", "r", "t", "y", "u", "i", "o", "p"]
  let secondRow = ["a", "s", "d", "f", "g", "h", "j", "k", "l"]
  let thirdRow = ["z", "x", "c", "v", "b", "n", "m"]
  let fourthRow = ["space"]

  let allRows:[[String]]

  init() {
    self.allRows = [firstRow, secondRow, thirdRow, fourthRow]
  }

then this other code:

  var body: some View {
    VStack(spacing: 9) {
      ForEach(allRows.indices) { row in
        let num = allRows[row].indices
        HStack(spacing: 0) {
          ForEach(num) { column in
            Button(action: {}) {
              Text(keyboardViewModel.allRows[row][column])
                .font(.system(size: 15, weight: .regular, design: .default))
                .foregroundColor(.white)
                .buttonStyle(PlainButtonStyle())
                .frame(width: keyWidth)
                .background(GeometryReader {
                  Color.clear.preference(key: KeyWidthKey.self,
                                         value: $0.frame(in: .local).size.height)
                })
                .contentShape(Rectangle())
            }
          }
        }.onPreferenceChange(KeyWidthKey.self) { keyWidth = $0 }

      }
    }
  }

struct KeyWidthKey: PreferenceKey {
  static var defaultValue: CGFloat { 0 }
  static func reduce(value: inout Value, nextValue: () -> Value) {
    value = max(value, nextValue())
  }
}

The idea is to render a keyyboard with four rows of keys.

These two lines

ForEach(keyboardViewModel.allRows.indices) { row in

and

ForEach(num) { column in

give me the error

Non-constant range: not an integer range

The first error points to indices and the second one to num.

Why is that? How do I solve this?

I would like to understand the problem.

found the problem. Thanks to the error message, the solution has nothing to do with anything, as expected.

Just add , id: \.self to both ForEach

found the problem

No! You found the solution! Thanks for coming back and sharing your solution. But also, please, take a moment and mark your answer as "Solved".