Well, this is interesting: according to David F. Sandberg, director of the upcoming Shazam!, the DCEU film will technically share a universe with his previous film.
That previous film was a horror film called Lights Out, about the avenging spirit of a girl named Diana which lashes out at the film’s protagonists. When responding to a tweet about another one of his films, Annabelle: Creation, Sandberg said that a character from Lights Out will appear in Shazam!, meaning that, technically, the two films share a world.
As pointed out by Screen Rant, that character will probably be Esther, a cameo character played by Sandberg’s wife, the actress and producer Lotta Losten, who has appeared in most of his films to date.
Let’s have some fun with this, though: In Lights Out, DC Comics exists, meaning that superheroes are... fiction. Meaning that, in the DCEU, it’s now canon that DC Comics also exist, parallel to the characters. Which means Batman was inspired by... himself? Does Tommy Westphall have something to do with this?
Shared universe or not, Shazam! is slated for an April 2019 release, and will star Zachary Levi as the boy-turned-adult-turned-superhero.