From 70c9f16f5e656942249651bfafc3357cd4bbf397 Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Tue, 15 Aug 2023 10:15:48 -0400
Subject: [PATCH] Address PR feedback

---
 .../src/System/Collections/Frozen/FrozenDictionary.cs           | 2 ++
 .../src/System/Collections/Frozen/FrozenSet.cs                  | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenDictionary.cs b/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenDictionary.cs
index 02ea95e4a8737..e4fbdcef00b3c 100644
--- a/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenDictionary.cs
+++ b/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenDictionary.cs
@@ -113,6 +113,8 @@ public static FrozenDictionary<TKey, TElement> ToFrozenDictionary<TSource, TKey,
         private static FrozenDictionary<TKey, TValue> CreateFromDictionary<TKey, TValue>(Dictionary<TKey, TValue> source)
             where TKey : notnull
         {
+            Debug.Assert(source.Count > 0, "Empty sources should have been filtered out by caller");
+
             IEqualityComparer<TKey> comparer = source.Comparer;
 
             // Optimize for value types when the default comparer is being used. In such a case, the implementation
diff --git a/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenSet.cs b/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenSet.cs
index ed472ff80666a..8c315f214fe03 100644
--- a/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenSet.cs
+++ b/src/libraries/System.Collections.Immutable/src/System/Collections/Frozen/FrozenSet.cs
@@ -59,6 +59,8 @@ public static FrozenSet<T> ToFrozenSet<T>(this IEnumerable<T> source, IEqualityC
 
         private static FrozenSet<T> CreateFromSet<T>(HashSet<T> source)
         {
+            Debug.Assert(source.Count > 0, "Empty sources should have been filtered out by caller");
+
             IEqualityComparer<T> comparer = source.Comparer;
 
             // Optimize for value types when the default comparer is being used. In such a case, the implementation