Rust Sudoku Validator

// This probably sucks and is horribly inefficient, but I'm still learning Rust.

type Row = [u32; 9];
type Sudoku = [Row; 9];

static SUDOKU: Sudoku = [
  [8, 2, 7, 1, 5, 4, 3, 9, 6],
  [9, 6, 5, 3, 2, 7, 1, 4, 8],
  [3, 4, 1, 6, 8, 9, 7, 5, 2],
  [5, 9, 3, 4, 6, 8, 2, 7, 1],
  [4, 7, 2, 5, 1, 3, 6, 8, 9],
  [6, 1, 8, 9, 7, 2, 4, 3, 5],
  [7, 8, 6, 2, 3, 5, 9, 1, 4],
  [1, 5, 4, 7, 9, 6, 8, 2, 3],
  [2, 3, 9, 8, 4, 1, 5, 6, 7]
];

static VALID_ROW: Row = [1, 2, 3, 4, 5, 6, 7, 8, 9];

fn is_valid(row: &[u32]) -> bool {
  let mut clone = [0u32; 9];
  clone.clone_from_slice(row);
  clone.sort();
  clone == VALID_ROW
}

fn rotate(sudoku: &Sudoku) -> Sudoku {
  let mut rotated = [[0u32; 9]; 9];
  for r in 0..9 {
    for c in 0..9 {
      rotated[c][r] = sudoku[r][c];
    }
  }
  rotated
}

fn chunk(sudoku: &Sudoku) -> Sudoku {
  let mut chunked = [[0u32; 9]; 9];
  let mut c = 0;
  let chunks = [0..3, 3..6, 6..9];
  for outer in chunks.iter() {
    for inner in chunks.iter() {
      let mut chunk: Vec<u32> = vec![];
      for o in outer.clone() {
        for i in inner.clone() {
          chunk.push(sudoku[o][i]);
        }
      }
      chunked[c].clone_from_slice(&chunk);
      c += 1;
    }
  }
  chunked
}

fn is_sudoku_valid(sudoku: &Sudoku) -> bool {
  sudoku.iter().map(|row| is_valid(row)).fold(true, |a, b| a && b)
}

fn validate(sudoku: &Sudoku) -> bool {
  is_sudoku_valid(sudoku) && is_sudoku_valid(&rotate(sudoku)) && is_sudoku_valid(&chunk(sudoku))
}

fn main() {
  println!("{:?}", validate(&SUDOKU));
}