I have a grid that ist configured like this:

$susy: (
  columns: susy-repeat(8), 
  gutters: 20px
)

Inside is a div-Container styled like this:

margin-left: span(1 wide of 8);
width: span(6 of 8)

Now I have a headline inside which need to take all 8 columns again. In Susy 2 I solved this use the bleed-Mixin. How do I implement this in Susy 3? As the result of the span-function is already a calc-Expression, I can not use calc and none of the parameters in the span-function takes negative value.