message: Fix test failure in rust 1.42
diff: @@ -2963,7 +2963,7 @@ mod test {
  (2, 2),
  vec![0, 2, 3],
  vec![0, 1, 1],
  - vec![2.0, f64::NAN, 2.0],
  + vec![2.0, std::f64::NAN, 2.0],
  );
  let onehot = mat.to_inner_onehot();
  