I don't believe there should be a GE before the issue of Brexit is done and dusted. As others have said, Brexit would dominate it, but it would then give legitimacy to anything else (tax cuts increases, health, education, defence spending, pensions, etc etc) over the next five years.
I have no doubt that a GE will be inevitable over the next few months because the government doesn't have a majority, but it shouldn't be held on a solely Brexit agenda.
We need a proper, honest, well informed, advisory referendum (possibly in two stages) to find out what the public really wants in 2019.