anchor.diff:          if (!String.instance(string).empty) {
               $dart$core.String oldString = this.toString();
               clear();
  -            delegate.write(String.instance((String.nativeValue(String.instance(oldString).spanTo(Integer.instance(index - 1))) + string) + String.nativeValue(String.instance(oldString).spanFrom(Integer.instance(index + length)))));
  +            _$delegate.write(String.instance((String.nativeValue(String.instance(oldString).spanTo(Integer.instance(index - 1))) + string) + String.nativeValue(String.instance(oldString).spanFrom(Integer.instance(index + length)))));
           }
           return this;
       }
  
positive.code:         }
          $dart$core.String oldString = this.toString();
          clear();
          delegate.write(String.instance((String.nativeValue(String.instance(oldString).spanTo(Integer.instance(index - 1))) + string) + String.nativeValue(String.instance(oldString).spanFrom(Integer.instance(index)))));
          return this;
      }
      StringBuilder insertCharacter([$dart$core.int index, Character character]) => insert(index, character.toString());
  
negative.code:     Sequence collect([Callable collecting]) {
          Sequence sequence;
          {
              Sequential tmp$5 = _$array.collect(collecting);
              if (!(tmp$5 is Sequence)) {
                  throw new AssertionError("Violated: nonempty sequence = array.collect(collecting)");
              }
  