get the most local symbol from `bindSym`

[jxy]

bindSym always returns all the symbols, local and larger scopes, for a 
variable. If I have 
    
    
    import macros
    var a = 0
    block:
      var a = "block"
      macro m: stmt =
        let s = bindsym"a"
        echo s.lisprepr
        result = newstmtlist()
      m()
    

I get 
    
    
    ClosedSymChoice(Sym(a), Sym(a))
    

How do I know which one is the actual local symbol, and which are shadowed?