In her own words
>“I have so many memories of Robin. There is no way I can share the jokes that we said and the things that we did,” said Goldberg. “Even years later, in 2016, it would still be a problem today. Those secrets will never be revealed.”
https://pagesix.com/2016/10/08/whoopi-goldberg-wont-reveal-secrets-held-with-late-robin-williams/amp/