Is it permissible to say "May our Lord have mercy on him" for an innovator?

It is not permissible to invoke mercy upon innovators (Ahl al-Bid'ah) whose innovation amounts to disbelief, if they die upon their innovation after the evidence has been established against them. This is based on the statement of Allah the Almighty: "And do not ever offer the funeral prayer for anyone of them who has died." As for those of them who are alive, one should supplicate for their guidance. However, if their innovation does not amount to disbelief, then it is permissible to invoke mercy upon them and to pray over their جنازة (funeral). Nevertheless, it is preferable for people of virtue to avoid praying over them.