[Bug c++/83818] g++ class template parameter deduction discards const qualifier

[bugzilla.gcc.karo at cupdev dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83818

--- Comment #2 from Karolin varner <bugzilla.gcc.karo at cupdev dot net> ---
Comment on attachment 43119
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43119
Test case

>template<typename T>
>struct tstruct {
>  T x;
>  tstruct(const T &x_) : x{x_} {}
>};
>
>int main() {
>  const tstruct s{2};
>  tstruct<int> &u = s;
>  s.x = 2;
>  return 0;
>}