anchor.diff:              $dart$core.int from = -1;
               $dart$core.int to = -1;
               {
  -                $dart$core.bool doFail$68 = true;
  -                $dart$core.Object element$70;
  -                Iterator iterator$69 = $package$span(Integer.instance(0), Integer.instance(end)).iterator();
  -                while ((element$70 = iterator$69.next()) is !Finished) {
  -                    Integer index = element$70 as Integer;
  +                $dart$core.bool doFail$34 = true;
  +                $dart$core.Object element$36;
  +                Iterator iterator$35 = $package$span(Integer.instance(0), Integer.instance(end)).iterator();
  +                while ((element$36 = iterator$35.next()) is !Finished) {
  +                    Integer index = element$36 as Integer;
                       {
  -                        $dart$core.Object tmp$71 = $this.getFromFirst(Integer.nativeValue(index));
  -                        if (!(null == tmp$71)) {
  +                        $dart$core.Object tmp$37 = $this.getFromFirst(Integer.nativeValue(index));
  +                        if (!(null == tmp$37)) {
                               $dart$core.Object elem;
  -                            elem = tmp$71;
  +                            elem = tmp$37;
                               if (!Boolean.nativeValue(trimming.f(elem) as Boolean)) {
                                   from = Integer.nativeValue(index);
  -                                doFail$68 = false;
  +                                doFail$34 = false;
                                   break;
                               }
                           }
                       }
                   }
  -                if (doFail$68) {
  +                if (doFail$34) {
                       return $package$empty;
                   }
               }
               {
  -                $dart$core.bool doFail$72 = true;
  -                $dart$core.Object element$74;
  -                Iterator iterator$73 = $package$span(Integer.instance(end), Integer.instance(0)).iterator();
  -                while ((element$74 = iterator$73.next()) is !Finished) {
  -                    Integer index = element$74 as Integer;
  +                $dart$core.bool doFail$38 = true;
  +                $dart$core.Object element$40;
  +                Iterator iterator$39 = $package$span(Integer.instance(end), Integer.instance(0)).iterator();
  +                while ((element$40 = iterator$39.next()) is !Finished) {
  +                    Integer index = element$40 as Integer;
                       {
  -                        $dart$core.Object tmp$75 = $this.getFromFirst(Integer.nativeValue(index));
  -                        if (!(null == tmp$75)) {
  +                        $dart$core.Object tmp$41 = $this.getFromFirst(Integer.nativeValue(index));
  +                        if (!(null == tmp$41)) {
                               $dart$core.Object elem;
  -                            elem = tmp$75;
  +                            elem = tmp$41;
                               if (!Boolean.nativeValue(trimming.f(elem) as Boolean)) {
                                   to = Integer.nativeValue(index);
  -                                doFail$72 = false;
  +                                doFail$38 = false;
                                   break;
                               }
                           }
                       }
                   }
  -                if (doFail$72) {
  +                if (doFail$38) {
                       return $package$empty;
                   }
               }
  
positive.code:     $dart$core.bool get empty => $outer$ceylon$language$Iterable.empty;
      Iterator iterator() => (() {
          Iterator iter = $outer$ceylon$language$Iterable.iterator();
          return new Iterable$partition$$anonymous$23_$$anonymous$24_(this, iter);
      })();
      $dart$core.String toString() => Iterable.$get$string(this);
      $dart$core.bool contains([$dart$core.Object element]) => Iterable.$contains(this, element);
  
negative.code:     Iterable takeWhile([Callable taking]) => Iterable.$takeWhile(this, taking);
      Iterable repeat([$dart$core.int times]) => Iterable.$repeat(this, times);
      Iterable by([$dart$core.int step]) => Iterable.$by(this, step);
      Iterable get coalesced => Iterable.$get$coalesced(this);
      Iterable get indexed => Iterable.$get$indexed(this);
      Iterable get paired => Iterable.$get$paired(this);
  