Compiler error when compiling with MSVC & C++20

[andreasWallner]

The std::result_of type trait was removed with C++20 in favor of std::invoke_result. With on of MSVCs latest updates they did this removal (if set to compile as C++20), leading to compile errors of clipp because of it's use in e.g.

clipp/include/clipp.h

Lines 160 to 163 in 2c32b2f

	check_is_callable(int) -> decltype(
	std::declval<Fn>()(std::declval<Args>()...),
	std::integral_constant<bool,
	std::is_same<Ret,typename std::result_of<Fn(Args...)>::type>::value>{} );

To reproduce you can run the testsuite with /std:c++latest when using at least MSVC16.7.3 (did not check if the change occured with this or an earlier version)

[Silveryard]

Is there an ETA on when this fix will be merged?

[FlyAndNotDown]

Same problems

[obi0ne]

Any plans for this to be released in upcoming new version. (1.2.4 ?)
so conan can provided updated versions that compiles with C++20 ?

Is this opensource still alive ?

[andreasWallner]

There is a fork by @GerHobbelt that includes this and quite a few other fixes: https://github.com/GerHobbelt/clipp