/// # Example
///
/// ```rust
+ /// # use std::fmt::Debug;
/// fn foo(x: &u32) -> impl Debug { *x }
/// ```
///
/// The function signature here would be:
///
- /// ```
+ /// ```ignore (illustrative)
/// for<'a> fn(&'a u32) -> Foo
/// ```
///
///
/// The *liberated* form of this would be
///
- /// ```
+ /// ```ignore (illustrative)
/// fn(&'a u32) -> u32
/// ```
///