From f14816144b6e680de653632a8c2ce02d2f4773c2 Mon Sep 17 00:00:00 2001
From: Yoh Deadfall <yoh.deadfall@hotmail.com>
Date: Thu, 2 Sep 2021 13:32:37 +0300
Subject: [PATCH 1/2] Compiler intrinsic based type nullability check

---
 .../Data/Converters/FuncValueConverter.cs          |  2 +-
 src/Avalonia.Base/Utilities/TypeUtilities.cs       | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs b/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
index 9ec600d2bc..c0a3c6ad0f 100644
--- a/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
+++ b/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
@@ -26,7 +26,7 @@ namespace Avalonia.Data.Converters
         /// <inheritdoc/>
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            if (value is TIn || (value == null && TypeUtilities.AcceptsNull(typeof(TIn))))
+            if (value is TIn || (value == null && TypeUtilities.AcceptsNull<TIn>()))
             {
                 return _convert((TIn)value);
             }
diff --git a/src/Avalonia.Base/Utilities/TypeUtilities.cs b/src/Avalonia.Base/Utilities/TypeUtilities.cs
index 179ded3549..0978308ef6 100644
--- a/src/Avalonia.Base/Utilities/TypeUtilities.cs
+++ b/src/Avalonia.Base/Utilities/TypeUtilities.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 
 namespace Avalonia.Utilities
 {
@@ -93,6 +94,17 @@ namespace Avalonia.Utilities
             return !type.IsValueType || IsNullableType(type);
         }
 
+        /// <summary>
+        /// Returns a value indicating whether null can be assigned to the specified type.
+        /// </summary>
+        /// <typeparam name="T">The type</typeparam>
+        /// <returns>True if the type accepts null values; otherwise false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool AcceptsNull<T>()
+        {
+            return default(T) is null;
+        }
+
         /// <summary>
         /// Returns a value indicating whether value can be casted to the specified type.
         /// If value is null, checks if instances of that type can be null.
@@ -102,7 +114,7 @@ namespace Avalonia.Utilities
         /// <returns>True if the cast is possible, otherwise false.</returns>
         public static bool CanCast<T>(object value)
         {
-            return value is T || (value is null && AcceptsNull(typeof(T)));
+            return value is T || (value is null && AcceptsNull<T>());
         }
 
         /// <summary>

From 0c20e122ba877db3ad702ce235858aef6ec590be Mon Sep 17 00:00:00 2001
From: Yoh Deadfall <yoh.deadfall@hotmail.com>
Date: Thu, 2 Sep 2021 13:36:47 +0300
Subject: [PATCH 2/2] Code deduplication

---
 src/Avalonia.Base/Data/Converters/FuncValueConverter.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs b/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
index c0a3c6ad0f..2385d4981c 100644
--- a/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
+++ b/src/Avalonia.Base/Data/Converters/FuncValueConverter.cs
@@ -26,7 +26,7 @@ namespace Avalonia.Data.Converters
         /// <inheritdoc/>
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            if (value is TIn || (value == null && TypeUtilities.AcceptsNull<TIn>()))
+            if (TypeUtilities.CanCast<TIn>(value))
             {
                 return _convert((TIn)value);
             }