We know full well that Batman is going to appear in the David Ayer film, though he isn't credited in the official list from Warner Brothers. However, the same list which is leaving Ben Affleck's Bruce Wayne out is including one of his soon-to-be buddies.
Warning! Some will consider this a spoiler for Suicide Squad! Continue only if you want to know which other member of the Justice League will cameo in Suicide Squad! You've been warned.
According to the final cast list, Ezra Miller's The Flash will be making an appearance in Suicide Squad. The cast list is in order of appearance in the film, indicating that The Flash will make his cameo after Captain Boomerang debuts on the screen. This backs up the popular theory from certain trailers that the scenes showing Captain Boomerang surrounded by lightning are actually him being caught by The Flash and eventually jailed (or at least something along those lines).
Check out a screenshot of the cast list below.
This is not the entire cast list, simply enough of it to show where Miller's The Flash comes into the mix. The list is pretty revealing. It looks like we'll start out with Will Smith's Deadshot which sounds promising, though Karen Fukuhara's Katana doesn't seem to come into play until much later in the game.
Suicide Squad hits theaters August 5.