anchor.diff:    Integer xor([Integer other])
       =>  new Integer(_value.toSigned(32) ^ other._value.toSigned(32));
   
  -  Integer get not => new Integer(~_value.toSigned(32));
  +  Integer get not => new Integer((~_value).toSigned(32));
   
     // Enumerable
     Integer neighbour([$dart$core.int offset]) => new Integer(this._value + offset);
  
positive.code: 
    Integer flip([$dart$core.int index]) {
      if (index < 0 || index > 31) {
        return new Integer(_value.toSigned(32));
      }
      $dart$core.int mask = (1 << index).toSigned(32);
      return new Integer(_value.toSigned(32) ^ mask);
  
negative.code: 
    Integer set([$dart$core.int index, $dart$core.bool bit = true]) {
      if (index < 0 || index > 31) {
        // Match JS behavior, for now
        // https://github.com/ceylon/ceylon/issues/5799
        //return new Integer(_value.toSigned(32));
        return this;
      }
      $dart$core.int mask = (1 << index).toSigned(32);
      if (bit) {
  