From 29b55bd6d008a70488fc9efec3866f39a4116cd9 Mon Sep 17 00:00:00 2001
From: xtqqczze <45661989+xtqqczze@users.noreply.github.com>
Date: Wed, 23 Oct 2024 02:25:04 +0100
Subject: [PATCH 1/2] Use `Unsafe.BitCast` for generic span casting

---
 .../src/System/Globalization/DateTimeFormat.cs                 | 2 +-
 .../src/System/Globalization/HebrewNumber.cs                   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Globalization/DateTimeFormat.cs b/src/libraries/System.Private.CoreLib/src/System/Globalization/DateTimeFormat.cs
index a7ca7828e6e493..2b5a9c80a11104 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Globalization/DateTimeFormat.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Globalization/DateTimeFormat.cs
@@ -754,7 +754,7 @@ internal static void AppendChar<TChar>(ref ValueListBuilder<TChar> result, char
             {
                 Debug.Assert(typeof(TChar) == typeof(byte));
                 var r = new Rune(ch);
-                r.EncodeToUtf8(MemoryMarshal.AsBytes(result.AppendSpan(r.Utf8SequenceLength)));
+                r.EncodeToUtf8(Unsafe.BitCast<Span<TChar>, Span<byte>>(result.AppendSpan(r.Utf8SequenceLength)));
             }
         }
 
diff --git a/src/libraries/System.Private.CoreLib/src/System/Globalization/HebrewNumber.cs b/src/libraries/System.Private.CoreLib/src/System/Globalization/HebrewNumber.cs
index e4c511e5b7c5a6..ac51013deff5c4 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Globalization/HebrewNumber.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Globalization/HebrewNumber.cs
@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Numerics;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 
@@ -211,7 +212,7 @@ internal static void Append<TChar>(ref ValueListBuilder<TChar> outputBuffer, int
                 else
                 {
                     Debug.Assert(typeof(TChar) == typeof(byte));
-                    Rune.DecodeLastFromUtf8(MemoryMarshal.AsBytes(outputBuffer.AsSpan()), out Rune value, out int bytesConsumed);
+                    Rune.DecodeLastFromUtf8(Unsafe.BitCast<ReadOnlySpan<TChar>, ReadOnlySpan<byte>>(outputBuffer.AsSpan()), out Rune value, out int bytesConsumed);
                     outputBuffer.Length -= bytesConsumed;
                     outputBuffer.Append(TChar.CastFrom('"'));
                     DateTimeFormat.AppendChar(ref outputBuffer, (char)value.Value);

From f488388d6cd03a77ba8cd53745d2e5b4680fc5da Mon Sep 17 00:00:00 2001
From: xtqqczze <45661989+xtqqczze@users.noreply.github.com>
Date: Thu, 24 Oct 2024 14:44:31 +0100
Subject: [PATCH 2/2] Update `Enum.EnumInfo`

---
 .../System.Private.CoreLib/src/System/Enum.EnumInfo.cs         | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Enum.EnumInfo.cs b/src/libraries/System.Private.CoreLib/src/System/Enum.EnumInfo.cs
index 07a205ce3016bd..59c788f56e7162 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Enum.EnumInfo.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Enum.EnumInfo.cs
@@ -3,6 +3,7 @@
 
 using System.Diagnostics;
 using System.Numerics;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 namespace System
@@ -36,7 +37,7 @@ public EnumInfo(bool hasFlagsAttribute, TStorage[] values, string[] names)
             public unsafe TResult[] CloneValues<TResult>() where TResult : struct
             {
                 Debug.Assert(sizeof(TStorage) == sizeof(TResult));
-                return MemoryMarshal.Cast<TStorage, TResult>(Values).ToArray();
+                return Unsafe.BitCast<ReadOnlySpan<TStorage>, ReadOnlySpan<TResult>>(Values).ToArray();
             }
         }
     }