From c4af8d01e12039ba514b952137c4a985fe6fd1a3 Mon Sep 17 00:00:00 2001
From: Noah Lev <camelidcamel@gmail.com>
Date: Mon, 24 Jun 2024 19:27:26 -0700
Subject: [PATCH] Impl `Update` for unit type `()`

This is useful in code that uses typestate.
---
 src/update.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/update.rs b/src/update.rs
index 3313746f..995b72fb 100644
--- a/src/update.rs
+++ b/src/update.rs
@@ -337,6 +337,7 @@ macro_rules! tuple_impl {
                 let ($($t,)*) = new_value;
                 let ($($u,)*) = unsafe { &mut *old_pointer };
 
+                #[allow(unused_mut)]
                 let mut changed = false;
                 $(
                     unsafe { changed |= Update::maybe_update($u, $t); }
@@ -348,6 +349,7 @@ macro_rules! tuple_impl {
 }
 
 // Create implementations for tuples up to arity 12
+tuple_impl!(;);
 tuple_impl!(A; a);
 tuple_impl!(A, B; a, b);
 tuple_impl!(A, B, C; a, b, c);