Compiler Conditionals not behaving the same with ASC2

I have been using compiler conditionals for a while,

before I could simply do something liek this:

if(CONFIG::myConditional){

     //compile this

}

else{

     //Compile this instead

}

currently this is broken with Air 3.8 and ASC2, I can only do something like this

CONFIG::myConditional{

     //compile this

}

But what about the "else"?