/// code. The most common case is something like this:
///
/// ```rust
+ /// # fn foo() -> i32 { 4 }
/// match foo() {
/// 22 => Default::default(), // call this type `?D`
/// _ => return, // return has type `!`
/// fallback to use based on whether there is a coercion pattern
/// like this:
///
- /// ```
+ /// ```ignore (not-rust)
/// ?Diverging -> ?V
/// ?NonDiverging -> ?V
/// ?V != ?NonDiverging