Poodlestrike
Banned
McCree can fire highly damaging extremely accurate rounds from far away, McCree can even outsnipe Hanzo or Widowmaker in the right hands. Deadeye instantly kills people if they don't hide. Bastion can't move.
The pistol can do a lot of damage even from range, and since Bastion is stationary a McCree can pretty much snipe him.
But that damage isn't any more extreme than Bastion's own. I guess he falls under the same counter heading as Widow or Pharah, hit him from outside his effective range, but considering that most of his kit is geared for closer-range fighting, and his lack of movement options like Tracer, I wouldn't really call him a counter.