<===> input.scss
foo {
  @if true {
    foo: true;
  } @elseif true {
    foo: false;
  } @else {
    foo: false;
  }

  @if true {
    bar: true;
  } @else if true {
    bar: false;
  } @else {
    bar: false;
  }
}

<===> output.css
foo {
  foo: true;
  bar: true;
}

<===> warning-dart-sass
DEPRECATION WARNING on line 4, column 5 of input.scss: 
@elseif is deprecated and will not be supported in future Sass versions.
Use "@else if" instead.
  ,
4 |   } @elseif true {
  |     ^^^^^^^
  '