C++ packed parameters

I'm trying to create a template method to construct a packed parameter list of types at compile time by sequentially appending a new member type. I tried with a construct to define an alias for the packed parameter I found on the WEB:

template <typename... T> using... type_pack = T;
using... my_types = type_pack<int, char, double>;

and then (and here I am guessing on the syntax)

using... list = my_types.., new_member; 

or maybe

using ... list = type_pack<my_types..., new_member>;

The compiler rejects the using... syntax. (I've tried g++ 9.4.0 with c++11,c++14 and c++17.)

$ c++ -o/dev/null -std=c++17 PackedParameters.cc 
PackedParameters.cc:9:31: error: expected identifier before ‘...’ token
    9 | template <typename... T> using... type_pack = T;
      |                               ^~~
PackedParameters.cc:9:31: error: expected unqualified-id before ‘...’ token
PackedParameters.cc:10:6: error: expected nested-name-specifier before ‘...’ token
   10 | using... my_types = type_pack<int, char, double>;
      |      ^~~
PackedParameters.cc:12:6: error: expected nested-name-specifier before ‘...’ token
   12 | using... my_list  = my_types..., int;

What am I missing?