<===> input.scss
$foo: 42;

.foo {
  content: $foo;
}

@for $i from 1337 to 1338 {
  $foo: $i !global;
}

.bar {
  content: $foo;
}

<===> output.css
.foo {
  content: 42;
}

.bar {
  content: 1337;
}