gistfile1.txt

    use std;                                                                                                                                                                  
                                                                                                                                                                              
    import std::dbg::refcount;                                                                                                                                                
                                                                                                                                                                              
type foo<T> = {                                                                                                                                                               
        mutable f: option<@T>                                                                                                                                                 
};                                                                                                                                                                            
                                                                                                                                                                              
fn upd<T>(&&f: foo<T>, g: fn(T)) {                                                                                                                                            
    {                                                                                                                                                                         
//            #error["rc=%?", refcount(option::get(f.f))];                                                                                                                    
    }                                                                                                                                                                         
    alt f.f {                                                                                                                                                                 
      some(v) {                                                                                                                                                               
//            #error["f.f=%? rc=%?", f.f, refcount(v)];                                                                                                                       
        {                                                                                                                                                                     
            g(*(copy v));                                                                                                                                                     
        }                                                                                                                                                                     
        let x = v;                                                                                                                                                            
//            #error["f.f=%? rc=%?", f.f, refcount(v)];                                                                                                                       
      }                                                                                                                                                                       
      none { }                                                                                                                                                                
    }                                                                                                                                                                         
}                                                                                                                                                                             
                                                                                                                                                                              
fn main() {                                                                                                                                                                   
    let x = @{mutable f: some(@3u)};                                                                                                                                          
        let y = x;                                                                                                                                                            
            #error["rc=%?", refcount(option::get(y.f))];                                                                                                                      
    upd(*x) {|v|                                                                                                                                                              
            #error["v=%? rc=%?", v, refcount(option::get(y.f))];                                                                                                              
            y.f = none;                                                                                                                                                       
    }                                                                                                                                                                         
}