Add null string support to implicit_cast, binary_numeric_promotion
Add null string support to implicit_cast, binary_numeric_promotion

Signed-off-by: Eli Skeggs <5085073edea185966a30aad7f06b91f6997b42e5@gmail.com>

bearhub/cub,bearhub/cub,bearhub/cub,bearhub/cub