Check for equality to null is unnecessarily explicit since null
is falsey in Sass.
a {
@if $x == null {}
/** ↑ ↑
* == or != null is unncessary */
}
true
The following patterns are considered warnings:
a {
@if $x == null {}
}
a {
@if $x != null {}
}
The following patterns are not considered warnings:
a {
@if $x {}
}
a {
@if not $x {}
}