Fix build error on .NET 6

Author: Sergio0694

CommunityToolkit.HighPerformance/Extensions/NullableExtensions.cs

@@ -50,9 +50,10 @@ public static ref T DangerousGetValueOrDefaultReference<T>(this ref T? value)
     /// <returns>A reference to the value of the input <see cref="Nullable{T}"/> instance, or a <see langword="null"/> <typeparamref name="T"/> reference.</returns>
     /// <remarks>The returned reference can be tested for <see langword="null"/> using <see cref="Unsafe.IsNullRef{T}(ref T)"/>.</remarks>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static unsafe ref T DangerousGetValueOrNullReference<T>(ref this T? value)
+    public static ref T DangerousGetValueOrNullReference<T>(ref this T? value)
         where T : struct
     {
+#if NET7_0_OR_GREATER
         ref T resultRef = ref Unsafe.NullRef<T>();
 
         // This pattern ensures that the resulting code ends up having a single return, and a single
@@ -69,14 +70,18 @@ public static unsafe ref T DangerousGetValueOrNullReference<T>(ref this T? value
         // This is better than what the code would've been with two separate returns in the method.
         if (value.HasValue)
         {
-#if NET7_0_OR_GREATER
             resultRef = ref Unsafe.AsRef(in Nullable.GetValueRefOrDefaultRef(in value));
-#else
-            resultRef = ref Unsafe.As<T?, RawNullableData<T>>(ref value).Value;
-#endif
         }
 
         return ref resultRef;
+#else
+        if (value.HasValue)
+        {
+            return ref Unsafe.As<T?, RawNullableData<T>>(ref value).Value;
+        }
+
+        return ref Unsafe.NullRef<T>();
+#endif
     }
 
 #if !NET7_0_OR_GREATER