Inconsistence of &

[Juan Sebastian Osuna]

According to lo sass-lang.com/documentation I can do the two following things:

.foo.bar .baz.bang, .bip.qux {
  $selector: &;
}

#main {
  color: black;
  &-sidebar { border: 1px solid; }
}

But while using 5.0.1 I get

Invalid CSS after " $selector: ": expected expression (e.g. 1px, bold), was "&;"
And
Invalid CSS after " &": expected "{", was "-sidebar {"

[Rafael Mendonça França]

Make sure you are using the right version of sass gem that enable the & in the selector name.