a nested @import with an @if inside removes the nesting

[nex3]

From sass/sass#2219:

Whenever you nest an @import and have @if in the root of the file it will lose its nesting.

index.scss

.nested {
  @import 'nesting';
}

_nesting.scss

@if true {
  .selector {
      color: #fff
  }
}

results into

.selector {
color: #fff;
}

This works though

& {
@if true {
  .selector {
      color: #fff
  }
}
}