Use interpolation for variables inside calc()

[sled]

Until now this was not compiled properly, i.e the output was

/* line 17, /Users/xxx/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/mtl-1.1.6/app/assets/stylesheets/mtl/extend/_chips.scss */
.chip .close {
  font-size: calc($chip-font-size + 3px);
  height: 22px;
  line-height: 23px;
  padding-left: calc($chip-font-size + 3px)/2;
}

[sled]

just noticed that $chip-font-size is also in px so one could write simply $chip-font-size + 3px not sure what was the problem in commit eb4e91c @ruinunes ?

[lgavillet]

👍