Vs2017 rror C3615: constexpr function 'strong::operator +=' cannot result in a constant expression

[unholytony]

Vs2017 seems to be complaining that the freestanding value_of functions are not constexpr.

	template < typename T, typename = impl::WhenSafeType<T>>
	STRONG_NODISCARD
	**constexpr** auto value_of( T&& t ) noexcept -> decltype( std::forward<T>( t ).value_of() )
	{
		return std::forward<T>( t ).value_of();
	}

	template < typename T, typename = impl::WhenNotSafeType<T>>
        **constexpr** T&& value_of( T&& t ) noexcept
	{
		return std::forward<T>( t );
	}

seems to fix it...

[unholytony]

oops sorry, constexpr was meant to be bold but its in a direct quote... you get the idea...

[rollbear]

Constexpr has been added, so this should be OK.