Get AST for type in macro

[GULPF]

I'm trying to get the AST for a type passed to a macro. The following works, 
but it requires a variable instead of a typedesc to be passed to the macro:
    
    
    macro typetraitImpl(x: untyped): string =
      newLit(getTypeImpl(x).treeRepr)
    
    template typetrait(T: typedesc): string =
      var x: T
      typetraitImpl(x)
    
    echo typetrait((int, int))
    # TupleConstr
    #   Sym "int"
    #   Sym "int"
    
    type X = (int, int)
    echo typetrait(X)
    # TupleConstr
    #   Sym "int"
    #   Sym "int"
    
    
    Run

I would have expected something like this to give the same result, but it does 
not: 
    
    
    macro typetrait(x: typedesc): string =
      newLit(getTypeImpl(x).treeRepr)
    
    echo typetrait((int, int))
    # BracketExpr
    #   Sym "typeDesc"
    #   TupleConstr
    #     Sym "int"
    #     Sym "int"
    
    type X = (int, int)
    echo typetrait(X)
    # BracketExpr
    #   Sym "typeDesc"
    #   Sym "X"
    
    
    
    Run

Is there any way to get the result from the first example without having an 
additional template?