LESS compiling error

/* This is the code from reset.less LINE:135) */

input[type="search"] {
  .box-sizing(content-box);
  -webkit-appearance: textfield;
}

/* This this is class its calling (.box-sizing) */
.box-sizing(@boxmodel) {
  -webkit-box-sizing: @boxmodel;
     -moz-box-sizing: @boxmodel;
          box-sizing: @boxmodel;
}

/* And this is the output when compiled  */
input[type="search"] {
  -webkit-box-sizing: content-box;
  -moz-box-sizing: content-box;
  box-sizing: content-box;
  -webkit-box-sizing: content-box;
  -moz-box-sizing: content-box;
  box-sizing: content-box;
  -webkit-appearance: textfield;
}

Problem was that i compiled the base Bootstrap framework and Responsive Bootstrap at the same time. Both of these frameworks @import mixin.less file separately if you are gonna install the whole framework at once, comment out the @import mixin.less, @import variables.less from responsive.less file.