[Bug c++/109142] auto tmp=*(data_type*)&v: expected primary-expression before ')' token

[xry111 at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109142

--- Comment #4 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
template <class T>
using data_type = decltype([](){return 1;}());

template <class T>
auto get_precision(T v) {
  auto tmp = *(data_type<T> *)&v;
  return tmp;
}

Clang and MSVC accept this with C++20, though I'm not sure if it's really valid
(I'm not familiar with latest C++ spec development).