Make sure we never hash NULLs
Make sure we never hash NULLs

nathanielbaxter/libminizinc,nathanielbaxter/libminizinc,jjdekker/libminizinc,jjdekker/libminizinc,nathanielbaxter/libminizinc,jjdekker/libminizinc,tias/libminizinc,tias/libminizinc,jjdekker/libminizinc,nathanielbaxter/libminizinc