anchor.diff:  
         case result.Subs.Count of
          0:begin
  -        result.Destroy;
  -        result:=nil;
  +        FreeAndNil(result);
          end;
          1:begin
           Left:=result.Subs[0];
           Left.Exact:=Left.Exact and result.Exact;
           result.Subs.Clear;
  -        result.Destroy;
  +        result.Free;
           result:=Left;
          end;
         end;
  
positive.code:        end;
        end;
        if not OK then begin
         result.Destroy;
         result:=TFLREPrefilterNode.Create;
         result.Operation:=FLREpfnoANY;
         result.Exact:=false;
  
negative.code: procedure TFLREUnicodeCharClass.Clear;
  begin
   while assigned(First) do begin
    First.Free;
   end;
   Inverted:=false;
   Canonicalized:=false;
  