pub fn comments() -> () {
    // line comment

    // line comment
    // line comment

    //

    //

    //
    //

    // line comment // test

    /* line comment */

    /* line comment */
    /* line comment */

    /* block
       comment
    */

    /*
       block
       comment
    */

    /**
       block
       comment
    */

    /**/

    /* */

    /***/

    // Not supported yet:
    //
    // Recursive block comment:
    // - This is valid: /* line /* test */ comment */
    // - This is invalid: /* line /* test comment */
}