I'm getting this error. I would like help knowing how deep "too deep" is - i.e. is there a rule of thumb for how many local variables are allowed? I've been constructing a number of structs with references and mappings to other structs, up to 4 deep. e.g. categories[categoryID].nominees[nomineeID].user.externalUserID. I have not been trying to recompile as I go, so I now need to refactor across the contract.
There are a couple of references to the error on Google, but none definitive on when it will occur.