Use of deprecated std::result_of

[matbech]

VS 15.5 with /std:c++latest complains about the deprecated use of std::result_of:
error C4996: 'std::result_of': warning STL4014: std::result_of and std::result_of_t are deprecated in C++17. They are superseded by std::invoke_result and std::invoke_result_t. You can define _SILENCE_CXX17_RESULT_OF_DEPRECATION_WARNING or _SILENCE_ALL_CXX17_DEPRECATION_WARNINGS to acknowledge that you have received this warning.

File: /detail/type_traits.hpp