From ec6cf5238ba70126e15cc8765fb979f6734e19a7 Mon Sep 17 00:00:00 2001
From: DocSvartz <svartzdoctor@gmail.com>
Date: Tue, 31 Mar 2026 15:23:06 +0500
Subject: [PATCH 1/3] feat(test): replace RequiredProperty test and new
 Polymorphic test

---
 .../WhenMappingRecordRegression.cs            | 17 +----
 .../WhenMappingRequiredPropertyRegression.cs  | 68 +++++++++++++++++++
 2 files changed, 69 insertions(+), 16 deletions(-)
 create mode 100644 src/Mapster.Tests/WhenMappingRequiredPropertyRegression.cs

diff --git a/src/Mapster.Tests/WhenMappingRecordRegression.cs b/src/Mapster.Tests/WhenMappingRecordRegression.cs
index 85d291e8..4a065274 100644
--- a/src/Mapster.Tests/WhenMappingRecordRegression.cs
+++ b/src/Mapster.Tests/WhenMappingRecordRegression.cs
@@ -443,22 +443,7 @@ public void FixCtorParamMapping()
             result.Order.Payment.CVV.ShouldBe("234");
             resultID.UserID.ShouldBe("256");
         }
-
-        [TestMethod]
-        public void RequiredProperty()
-        {
-            var source = new Person553 { FirstMidName = "John", LastName = "Dow" };
-            var destination = new Person554 { ID = 245, FirstMidName = "Mary", LastName = "Dow" };
-                        
-            var s = source.BuildAdapter().CreateMapToTargetExpression<Person554>();
-
-            var result = source.Adapt(destination);
-
-            result.ID.ShouldBe(245);
-            result.FirstMidName.ShouldBe(source.FirstMidName);
-            result.LastName.ShouldBe(source.LastName);
-        }
-
+               
         /// <summary>
         /// https://github.com/MapsterMapper/Mapster/issues/842
         /// </summary>
diff --git a/src/Mapster.Tests/WhenMappingRequiredPropertyRegression.cs b/src/Mapster.Tests/WhenMappingRequiredPropertyRegression.cs
new file mode 100644
index 00000000..a578321b
--- /dev/null
+++ b/src/Mapster.Tests/WhenMappingRequiredPropertyRegression.cs
@@ -0,0 +1,68 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Shouldly;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Mapster.Tests
+{
+    [TestClass]
+    public class WhenMappingRequiredPropertyRegression
+    {
+        [TestMethod]
+        public void RequiredProperty()
+        {
+            var source = new Person553 { FirstMidName = "John", LastName = "Dow" };
+            var destination = new Person554 { ID = 245, FirstMidName = "Mary", LastName = "Dow" };
+
+            var s = source.BuildAdapter().CreateMapToTargetExpression<Person554>();
+
+            var result = source.Adapt(destination);
+
+            result.ID.ShouldBe(245);
+            result.FirstMidName.ShouldBe(source.FirstMidName);
+            result.LastName.ShouldBe(source.LastName);
+        }
+
+        [TestMethod]
+        public void PolymorphicMappingToAbstractClassCompileWithoutError()
+        {
+            var config = TypeAdapterConfig.GlobalSettings;
+
+            config.NewConfig<ConcreteSource, ConcreteDestination>();
+
+            config.NewConfig<AbstractSource, AbstractDestination>()
+                .Include<ConcreteSource, ConcreteDestination>();
+
+            Should.NotThrow(() =>
+            {
+                config.Compile();
+            });
+
+        }
+    }
+
+    #region TestClasses
+
+    public abstract class AbstractSource
+    {
+        public abstract string Name { get; }
+    }
+
+    public class ConcreteSource : AbstractSource
+    {
+        public override string Name => "Test";
+    }
+
+    public abstract class AbstractDestination
+    {
+        public required string Name { get; set; }
+    }
+
+    public class ConcreteDestination : AbstractDestination
+    {
+
+    }
+
+    #endregion TestClasses
+}

From a06ce0287a305f09ccecd9c21107433b06d00e56 Mon Sep 17 00:00:00 2001
From: DocSvartz <svartzdoctor@gmail.com>
Date: Tue, 31 Mar 2026 15:29:19 +0500
Subject: [PATCH 2/3] fix: #906 - InvalidCastException when using polymorphic
 mapping with required properties

---
 src/Mapster/Adapters/BaseAdapter.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Mapster/Adapters/BaseAdapter.cs b/src/Mapster/Adapters/BaseAdapter.cs
index 65c9d0f9..dba50681 100644
--- a/src/Mapster/Adapters/BaseAdapter.cs
+++ b/src/Mapster/Adapters/BaseAdapter.cs
@@ -219,7 +219,7 @@ protected Expression CreateBlockExpressionBody(Expression source, Expression? de
                 .Where(x => x.GetCustomAttributes()
                 .Any(y => y.GetType().FullName == "System.Runtime.CompilerServices.RequiredMemberAttribute"));
 
-            if (requiremembers.Count() != 0)
+            if (requiremembers.Count() != 0 && !arg.DestinationType.IsAbstract)
                 set = CreateInlineExpression(source, arg.CloneWith(MapType.ApplyNullPropagation), true);
             else
                 set = CreateInstantiationExpression(transformedSource, destination, arg);

From c049cf6f9a56aaaa57dff87e8670c51f5273d907 Mon Sep 17 00:00:00 2001
From: DocSvartz <svartzdoctor@gmail.com>
Date: Tue, 31 Mar 2026 15:35:58 +0500
Subject: [PATCH 3/3] chore: Bump Version to 10.0.7-pre03

---
 src/Directory.Build.props | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Directory.Build.props b/src/Directory.Build.props
index 8ce13048..064b39cf 100644
--- a/src/Directory.Build.props
+++ b/src/Directory.Build.props
@@ -2,7 +2,7 @@
 	<PropertyGroup>
 		<!-- Properties related to build/pack -->
         <IsPackable>false</IsPackable>
-		<Version>10.0.7-pre02</Version>
+		<Version>10.0.7-pre03</Version>
 		<MapsterPluginsTFMs>netstandard2.0;net10.0;net9.0;net8.0</MapsterPluginsTFMs>
 		<MapsterTFMs>netstandard2.0;net10.0;net9.0;net8.0</MapsterTFMs>
 		<MapsterEFCoreTFMs>net10.0;net9.0;net8.0</MapsterEFCoreTFMs>