static O[] primitiveArrayToBoxed(O a) {
  if (a == null) null;
  if (a cast int[]) {
    int n = a.length;
    Int[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  if (a cast char[]) {
    int n = a.length;
    Char[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  if (a cast bool[]) {
    int n = a.length;
    Bool[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  if (a cast short[]) {
    int n = a.length;
    Short[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  if (a cast long[]) {
    int n = a.length;
    Long[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  if (a cast float[]) {
    int n = a.length;
    Float[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  if (a cast double[]) {
    int n = a.length;
    Double[] b = new[n];
    for i to n: b[i] = a[i];
    ret b;
  }
  fail("Not a primitive array: " + _getClass(a));
}