error[E0308]: mismatched types
  --> $DIR/issue-102964.rs:5:41
   |
LL | fn bar_function<T>(function: Foo<T>) -> RcFoo<T> {
   |    ------------                         ^^^^^^^^ expected `Rc<&dyn Fn(&'a T)>`, found `()`
   |    |
   |    implicitly returns `()` as its body has no tail or `return` expression
   |
   = note: expected struct `Rc<&dyn for<'a> Fn(&'a T)>`
           found unit type `()`
help: consider returning the local binding `rc`
   |
LL ~     let rc = Rc::new(function);
LL +     rc
   |

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.