magnacarto/mss/tests/006-nested-rule.mss

#class {
    #class1{
        line-width: 13;
    }
}

#class {
    #class1{
        line-width: 13;
    }
    #class1{
        line-width: 13;
    }
}

#class {
    [filter='foo'] {
        line-width: 13;
    }
    line-width: 13;
    #class1{
        line-width: 13;
    }
    line-width: 13
}