From https://users.rust-lang.org/t/does-implementing-deref-affect-the-lifetime-bounds-of-all-other-methods/ --- Code: ~~http://is.gd/AkyE699~~ http://is.gd/AkyE69 If the Deref is removed, the code compiles. Presumably, the inclusion of the Deref implementation on the trait object causes the lifetime bounds to change on the do_something method.