My Blue Valentine (1990)*

Steve Martin is a Mob informant in the Witness Protection Program. He has black hair instead of white—I think this is just his character, not part of his disguise—and he pushes a shopping cart in a supermarket (possibly also on the movie poster). Maybe he meets Rick Moranis? I don't remember anything else about this goddamned movie.

Whatever happened to Rick Moranis, anyway?

* Important note: This movie is called My Blue Heaven. Blue Valentine is a very different movie.