Gulp-ruby-sass and "! global" statement

[ludo237]

Hello everyone.
I'm not a SCSS expert so, maybe, I'm writing it wrong but when I try to do something like

[Other code ]
  $prefix-webkit: $original-prefix-webkit ! global;
[Other code]

Gulp throws me an exception
Syntax error: Invalid CSS after "...dules, $name) !": expected identifier, was " global;"

The solution is easy, just remove the ! near the global identifier but I know that that is a correct SCSS statement so gulp might be wrong. Anyone has this issue?
I'm using

[gulp] CLI version 3.6.2
[gulp] Local version 3.8.0

[sindresorhus]

This is not the right place to get Sass support. Try StackOverflow or the Sass issue tracker.