The following code example is taken from the book
C++17 - The Complete Guide by Nicolai M. Josuttis, Leanpub, 2017
The code is licensed under a Creative Commons Attribution 4.0 International License. Creative Commons License

// raw code

#include <type_traits> // for true_type, false_type, and void_t

// primary template:
template<typename, typename = std::void_t<>>
struct HasDelete
: std::false_type {

// partial specialization (may be SFINAE'd away):
template<typename T>
struct HasDelete<T, std::void_t<decltype(T::operator delete(nullptr))>>
: std::true_type {