From 68baac36b438fc3ef1ec59fcdcff60e8304f140d Mon Sep 17 00:00:00 2001
From: Steve Klabnik <steve@steveklabnik.com>
Date: Mon, 12 Jan 2015 16:07:44 -0500
Subject: [PATCH] Add enum discriminats to the reference.

Fixes #15755
---
 src/doc/reference.md | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/doc/reference.md b/src/doc/reference.md
index 623097b2fc90f..59407a82e671e 100644
--- a/src/doc/reference.md
+++ b/src/doc/reference.md
@@ -1413,6 +1413,27 @@ a = Animal::Cat { name: "Spotty".to_string(), weight: 2.7 };
 In this example, `Cat` is a _struct-like enum variant_,
 whereas `Dog` is simply called an enum variant.
 
+Enums have a discriminant. You can assign them explicitly:
+
+```
+enum Foo {
+    Bar = 123,
+}
+```
+
+If a discriminant isn't assigned, they start at zero, and add one for each
+variant, in order.
+
+You can cast an enum to get this value:
+
+```
+# enum Foo { Bar = 123 }
+let x = Foo::Bar as u32; // x is now 123u32
+```
+
+This only works as long as none of the variants have data attached. If
+it were `Bar(i32)`, this is disallowed.
+
 ### Constant items
 
 ```{.ebnf .gram}