Bastion + Mercy and/or Reinhardt counter

I have no problems with dealing with Bastion when he's alone, but with a Mercy or Reinhardt with him, he's literally the most annoying thing.

If you jump in close to him, you can't aim the Mercy because he's going to mow you down if you don't get him. When you do kill him, Mercy resurrects him. If it's a Reinhardt, most people who can run up to Bastion can't survive more than a few hits from Reinhard, save maybe for D.Va.

What's heroes/tactics can counter this team composition.