From 3e8504c79e13050af39796a09b23a0d66518add0 Mon Sep 17 00:00:00 2001
From: Alex Peck <amwpeck@gmail.com>
Date: Sat, 9 Dec 2023 14:17:30 -0800
Subject: [PATCH] Nullability: verify ReferenceCount<object>(null) GetHashCode
 (#539)

---
 BitFaster.Caching.UnitTests/ReferenceCountTests.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/BitFaster.Caching.UnitTests/ReferenceCountTests.cs b/BitFaster.Caching.UnitTests/ReferenceCountTests.cs
index 7824b657..429d2001 100644
--- a/BitFaster.Caching.UnitTests/ReferenceCountTests.cs
+++ b/BitFaster.Caching.UnitTests/ReferenceCountTests.cs
@@ -58,5 +58,15 @@ public void WhenObjectsAreDifferentHashcodesAreDifferent()
 
             a.GetHashCode().Should().NotBe(b.GetHashCode());
         }
+
+        [Fact]
+        public void WhenObjectIsNullGetHashCodeDoesntThrow()
+        {
+            var a = new ReferenceCount<object>(null);
+
+            // nullable static analysis suggests this is broken, but it is legal to call
+            // EqualityComparer<TValue>.Default.GetHashCode(null)
+            a.GetHashCode();
+        }
     }
 }