sass/susy/language/susy/_validation.scss in susy-2.1.3 vs sass/susy/language/susy/_validation.scss in susy-2.2.0.beta.2

@@ -6,10 +6,10 @@
 // --------------------
 @function valid-column-math(
   $math,
   $column-width
 ) {
-  @if $math == static and not $column-width {
+  @if $math == static and not($column-width) {
     @warn 'Static math requires a valid column-width setting.';
   } @else {
     @return $column-width;
   }
 }