anchor.diff:      }
       $dart$core.int get lastIndex => $outer$ceylon$language$Sequence.lastIndex;
       $dart$core.int size;
  -    $dart$core.Object getFromFirst([$dart$core.int index]) => (() {
  -        if ((index >= 0) && (index < size)) {
  -            return $capture$Sequence$collect$collecting.f(Sequence.$_$getElement($outer$ceylon$language$Sequence, index));
  -        } else {
  -            return null;
  -        }
  -    })();
  +    $dart$core.Object getFromFirst([$dart$core.int index]) => (index >= 0) && (index < size) ? $capture$Sequence$collect$collecting.f(Sequence.$_$getElement($outer$ceylon$language$Sequence, index)) : null;
       $dart$core.bool operator ==($dart$core.Object that) => List.$equals(this, that);
       $dart$core.int get hashCode => List.$get$hash(this);
       $dart$core.String toString() => Collection.$get$string(this);
  
positive.code:                 }
              }
          }
          return (() {
              if (((_$index - $outer$ceylon$language$List$Patch._$from) >= 0) && ((_$index - $outer$ceylon$language$List$Patch._$from) < $outer$ceylon$language$List$Patch._$list.size)) {
                  return $capture$$patchIter.next();
              } else {
                  return $capture$$iter.next();
              }
          })();
      }
      $dart$core.String toString() => ("" + $outer$ceylon$language$List$Patch.toString()) + ".iterator()";
  }
  
negative.code:     Sequential get rest => ((Sequential $lhs$) => null == $lhs$ ? $outer$ceylon$language$Sequence.span(Integer.instance(size - 2), Integer.instance(0)) : $lhs$)(size == 1 ? $package$empty : null);
      Sequence get reversed => $outer$ceylon$language$Sequence;
      $dart$core.Object getFromFirst([$dart$core.int index]) => $outer$ceylon$language$Sequence.getFromFirst((size - 1) - index);
      Sequential measure([Integer from, $dart$core.int length]) => length > 0 ? (() {
          $dart$core.int start = (size - 1) - Integer.nativeValue(from);
          return $outer$ceylon$language$Sequence.span(Integer.instance(start), Integer.instance((start - length) + 1));
      })() : $package$empty;
      Sequential span([Integer from, Integer to]) => $outer$ceylon$language$Sequence.span(to, from);
      Sequential spanFrom([Integer from]) => (() {
          $dart$core.int endIndex = size - 1;
          return Integer.nativeValue(from) <= endIndex ? $outer$ceylon$language$Sequence.span(Integer.instance(endIndex - Integer.nativeValue(from)), Integer.instance(0)) : $package$empty;
      })();
      Sequential spanTo([Integer to]) => Integer.nativeValue(to) >= 0 ? (() {
          $dart$core.int endIndex = size - 1;
          return $outer$ceylon$language$Sequence.span(Integer.instance(endIndex), Integer.instance(endIndex - Integer.nativeValue(to)));
      })() : $package$empty;
      Iterator iterator() => (() {
          Sequence outerList = $outer$ceylon$language$Sequence;
          return new Sequence$Reverse$$anonymous$0_(this, outerList);
  