An empty control flow directive is one that doesn't contain any declaration. Empty control flow directives are useless and should be removed.

Noncompliant Code Example

@if $x == 0 {
} @else {
}

@while $x == 0 {}

Compliant Solution

@if $x == 0 {
  do-something();
} @else {
  do-something-else();
}

@while $x == 0 {
  do-something();
}