首楞嚴義疏注經 5.391

5.391

前猶見水，今合真空無水可得，皆如來藏，故云亡身，即證法空也。

Previously he still saw water, but now he unites with true emptiness, and there is no water to be found; all is the tathāgatagarbha. Therefore it says 'I lost [attachment to] the body,' which is the realization of the emptiness of dharmas.