From 3c721174f1bec9ae22bd34ea479da0c5397a9124 Mon Sep 17 00:00:00 2001
From: Tanner Gooding <tagoo@outlook.com>
Date: Wed, 10 Jul 2024 09:57:52 -0700
Subject: [PATCH] Ensure that `char` doesn't box when using generic math

---
 .../System.Private.CoreLib/src/System/Char.cs | 75 ++++++++++++++++++-
 1 file changed, 72 insertions(+), 3 deletions(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Char.cs b/src/libraries/System.Private.CoreLib/src/System/Char.cs
index 7df1b14afc0332..085ff51ef9051e 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Char.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Char.cs
@@ -1159,6 +1159,9 @@ public static int ConvertToUtf32(string s, int index)
         // IBinaryInteger
         //
 
+        /// <inheritdoc cref="IBinaryInteger{TSelf}.DivRem(TSelf, TSelf)" />
+        static (char Quotient, char Remainder) IBinaryInteger<char>.DivRem(char left, char right) => ((char, char))Math.DivRem(left, right);
+
         /// <inheritdoc cref="IBinaryInteger{TSelf}.LeadingZeroCount(TSelf)" />
         static char IBinaryInteger<char>.LeadingZeroCount(char value) => (char)(BitOperations.LeadingZeroCount(value) - 16);
 
@@ -1446,6 +1449,60 @@ bool IBinaryInteger<char>.TryWriteLittleEndian(Span<byte> destination, out int b
         /// <inheritdoc cref="INumberBase{TSelf}.Abs(TSelf)" />
         static char INumberBase<char>.Abs(char value) => value;
 
+        /// <inheritdoc cref="INumberBase{TSelf}.CreateChecked{TOther}(TOther)" />
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        static char INumberBase<char>.CreateChecked<TOther>(TOther value)
+        {
+            char result;
+
+            if (typeof(TOther) == typeof(char))
+            {
+                result = (char)(object)value;
+            }
+            else if (!TryConvertFromChecked(value, out result) && !TOther.TryConvertToChecked(value, out result))
+            {
+                ThrowHelper.ThrowNotSupportedException();
+            }
+
+            return result;
+        }
+
+        /// <inheritdoc cref="INumberBase{TSelf}.CreateSaturating{TOther}(TOther)" />
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        static char INumberBase<char>.CreateSaturating<TOther>(TOther value)
+        {
+            char result;
+
+            if (typeof(TOther) == typeof(char))
+            {
+                result = (char)(object)value;
+            }
+            else if (!TryConvertFromSaturating(value, out result) && !TOther.TryConvertToSaturating(value, out result))
+            {
+                ThrowHelper.ThrowNotSupportedException();
+            }
+
+            return result;
+        }
+
+        /// <inheritdoc cref="INumberBase{TSelf}.CreateTruncating{TOther}(TOther)" />
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        static char INumberBase<char>.CreateTruncating<TOther>(TOther value)
+        {
+            char result;
+
+            if (typeof(TOther) == typeof(char))
+            {
+                result = (char)(object)value;
+            }
+            else if (!TryConvertFromTruncating(value, out result) && !TOther.TryConvertToTruncating(value, out result))
+            {
+                ThrowHelper.ThrowNotSupportedException();
+            }
+
+            return result;
+        }
+
         /// <inheritdoc cref="INumberBase{TSelf}.IsCanonical(TSelf)" />
         static bool INumberBase<char>.IsCanonical(char value) => true;
 
@@ -1518,7 +1575,11 @@ bool IBinaryInteger<char>.TryWriteLittleEndian(Span<byte> destination, out int b
 
         /// <inheritdoc cref="INumberBase{TSelf}.TryConvertFromChecked{TOther}(TOther, out TSelf)" />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        static bool INumberBase<char>.TryConvertFromChecked<TOther>(TOther value, out char result)
+        static bool INumberBase<char>.TryConvertFromChecked<TOther>(TOther value, out char result) => TryConvertFromChecked(value, out result);
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static bool TryConvertFromChecked<TOther>(TOther value, out char result)
+            where TOther : INumberBase<TOther>
         {
             // In order to reduce overall code duplication and improve the inlinabilty of these
             // methods for the corelib types we have `ConvertFrom` handle the same sign and
@@ -1580,7 +1641,11 @@ static bool INumberBase<char>.TryConvertFromChecked<TOther>(TOther value, out ch
 
         /// <inheritdoc cref="INumberBase{TSelf}.TryConvertFromSaturating{TOther}(TOther, out TSelf)" />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        static bool INumberBase<char>.TryConvertFromSaturating<TOther>(TOther value, out char result)
+        static bool INumberBase<char>.TryConvertFromSaturating<TOther>(TOther value, out char result) => TryConvertFromSaturating(value, out result);
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static bool TryConvertFromSaturating<TOther>(TOther value, out char result)
+            where TOther : INumberBase<TOther>
         {
             // In order to reduce overall code duplication and improve the inlinabilty of these
             // methods for the corelib types we have `ConvertFrom` handle the same sign and
@@ -1643,7 +1708,11 @@ static bool INumberBase<char>.TryConvertFromSaturating<TOther>(TOther value, out
 
         /// <inheritdoc cref="INumberBase{TSelf}.TryConvertFromTruncating{TOther}(TOther, out TSelf)" />
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        static bool INumberBase<char>.TryConvertFromTruncating<TOther>(TOther value, out char result)
+        static bool INumberBase<char>.TryConvertFromTruncating<TOther>(TOther value, out char result) => TryConvertFromTruncating(value, out result);
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static bool TryConvertFromTruncating<TOther>(TOther value, out char result)
+            where TOther : INumberBase<TOther>
         {
             // In order to reduce overall code duplication and improve the inlinabilty of these
             // methods for the corelib types we have `ConvertFrom` handle the same sign and