The following code:

    import std.stdio;
    import std.traits;

    void fn(T...)(T fns)
    {
        foreach(fn; fns)
        {
            writefln( "%s", ParameterTypeTuple!(fn)[0].mangleof );
        }
    }

    void main()
    {
        void a(int x) {}
        void b(double y) {}
        void c(Object z) {}

        fn(&a, &b, &c);
    }

Prints:

    i
    i
    i

When the type output should be int, double, Object, respectively.