Add example

src/statements.md

@@ -75,6 +75,17 @@ If the pattern does not match (this requires it to be refutable), the `else`
 block is executed.
 The `else` block must always diverge (evaluate to the [never type]).
 
+```rust
+let (mut v, w) = (vec![1, 2, 3], 42); // The bindings may be mut or const
+let Some(t) = v.pop() else { // Refutable patterns require an else block
+    panic!(); // The else block must diverge
+};
+let [u, v] = [v[0], v[1]] else { // This pattern is irrefutable, so the compiler
+                                 // will lint as the else block is redundant.
+    panic!();
+};
+```
+
 ## Expression statements
 
 > **<sup>Syntax</sup>**\