<===> _module.scss
.okay {
  background: green;
}

@if true {
  .broken {
    background: red;
  }
}
<===> input.scss
.wrapper-class {
  @import 'module';
}
<===> output.css
.wrapper-class .okay {
  background: green;
}
.wrapper-class .broken {
  background: red;
}