Lambdas in constexpr are only allowed from C++17. The functions returned from isValid cannot be used in a constexpr context in C++14.
Fixes #455 (closed). Tested with clang 3.8 which doesn't support constexpr lambdas.
Lambdas in constexpr are only allowed from C++17. The functions returned from isValid cannot be used in a constexpr context in C++14.
Fixes #455 (closed). Tested with clang 3.8 which doesn't support constexpr lambdas.