Did Corey Haim and Feldman both star in the movie lost boys?

That's close, but not quite right!

While both Corey Haim and Corey Feldman were popular teen stars in the 80s and 90s, only Corey Feldman starred in The Lost Boys (1987). He played the role of "Edgar Frog" alongside Jason Patric and Kiefer Sutherland.

Corey Haim did not appear in The Lost Boys.