From f39a4e17c8278b473323c4910d878b11389fe0c3 Mon Sep 17 00:00:00 2001
From: Jonathan Johnson <jon@khonsulabs.com>
Date: Thu, 28 Nov 2024 10:02:06 -0800
Subject: [PATCH] Implement Add for Generation

Given the incrementing nature of Generation, adding two generations
together and comparing the results of doing the same with a potentially
updated pair of generations will always be not-equal if either or both
change with the only edge case being if the total changes exactly equals
usize::MAX.

Thus this can be used to combine knowledge of multiple generations into
a single generation safely.
---
 src/value.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/value.rs b/src/value.rs
index a150fe636..0c8b4c24e 100644
--- a/src/value.rs
+++ b/src/value.rs
@@ -2622,6 +2622,14 @@ impl Generation {
     }
 }
 
+impl Add for Generation {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Self(self.0.wrapping_add(rhs.0))
+    }
+}
+
 /// A type that can convert into a `ReadOnly<T>`.
 pub trait IntoReadOnly<T> {
     /// Returns `self` as a `ReadOnly`.