From 5e941877fe0619497aced26243123b0c853b517d Mon Sep 17 00:00:00 2001
From: Steve Klabnik <steve@steveklabnik.com>
Date: Fri, 29 May 2015 12:37:18 -0400
Subject: [PATCH] Add syntax for multiple lifetimes

Fixes #25417
---
 src/doc/trpl/lifetimes.md | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/doc/trpl/lifetimes.md b/src/doc/trpl/lifetimes.md
index 04ae4c7ccf3cc..580960b7e8029 100644
--- a/src/doc/trpl/lifetimes.md
+++ b/src/doc/trpl/lifetimes.md
@@ -134,8 +134,29 @@ x: &'a i32,
 # }
 ```
 
-uses it. So why do we need a lifetime here? We need to ensure that any
-reference to the contained `i32` does not outlive the containing `Foo`.
+uses it. So why do we need a lifetime here? We need to ensure that any reference
+to a `Foo` cannot outlive the reference to an `i32` it contains.
+
+If you have multiple references, you can use the same lifetime multiple times:
+
+```rust
+fn x_or_y<'a>(x: &'a str, y: &'a str) -> &'a str {
+#    x
+# }
+```
+
+This says that `x` and `y` both are alive for the same scope, and that the
+return value is also alive for that scope. If you wanted `x` and `y` to have
+different lifetimes, you can use multiple lifetime parameters:
+
+```rust
+fn x_or_y<'a, 'b>(x: &'a str, y: &'b str) -> &'a str {
+#    x
+# }
+```
+
+In this example, `x` and `y` have different valid scopes, but the return value
+has the same lifetime as `x`.
 
 ## Thinking in scopes