We have SuspenseList for the tree view but not when printing JSX.

When we fallthrough here we call getDisplayName with a symbol, because we assume that if it's not a string, then it's a function. We should be checking whether it is a function before calling getDisplayName.

Subsequently if we call getDisplayName with a symbol we get the error invalid value used as weak map key which messes up things after that. I think that's the actual cause of #19364