This component-private function invokes the specified visitor with the active alternative object of the specified variant and implicitly converts the return type to (template parameter) t_RET. The pre-C++17 implementation is limited to invocations of the form visitor(variant). The behavior is undefined unless (template parameter) t_INDEX is the index of the active alternative.
Declared in <bslstl_variant.h>
static
t_RET
functionImpl(
t_VISITOR&& visitor,
t_VARIANT&& variant);