diff --git a/test/Riok.Mapperly.IntegrationTests/Mapper/StaticTestMapper.cs b/test/Riok.Mapperly.IntegrationTests/Mapper/StaticTestMapper.cs
index 155cccf91c..f3c186b63d 100644
--- a/test/Riok.Mapperly.IntegrationTests/Mapper/StaticTestMapper.cs
+++ b/test/Riok.Mapperly.IntegrationTests/Mapper/StaticTestMapper.cs
@@ -95,8 +95,8 @@ public static void MapExistingList(List<string> src, List<int> dst)
         [MapDerivedType<ExistingObjectTypeA, ExistingObjectTypeA>]
         [MapDerivedType<ExistingObjectTypeB, ExistingObjectTypeB>]
 #else
-        [MapDerivedType(typeof(ExistingObjectTypeA), typeof(ExistingObjectTypeADto))]
-        [MapDerivedType(typeof(ExistingObjectTypeB), typeof(ExistingObjectTypeBDto))]
+        [MapDerivedType(typeof(ExistingObjectTypeA), typeof(ExistingObjectTypeA))]
+        [MapDerivedType(typeof(ExistingObjectTypeB), typeof(ExistingObjectTypeB))]
 #endif
         public static partial void MapToDerivedExisting(ExistingObjectBase source, ExistingObjectBase target);
 
diff --git a/test/Riok.Mapperly.IntegrationTests/_snapshots/StaticMapperTest.SnapshotGeneratedSource_NET6_0.verified.cs b/test/Riok.Mapperly.IntegrationTests/_snapshots/StaticMapperTest.SnapshotGeneratedSource_NET6_0.verified.cs
index 3d77b56c3a..fcbbf9df91 100644
--- a/test/Riok.Mapperly.IntegrationTests/_snapshots/StaticMapperTest.SnapshotGeneratedSource_NET6_0.verified.cs
+++ b/test/Riok.Mapperly.IntegrationTests/_snapshots/StaticMapperTest.SnapshotGeneratedSource_NET6_0.verified.cs
@@ -473,6 +473,23 @@ object x when typeof(TTarget).IsAssignableFrom(typeof(object)) => (TTarget)(obje
             };
         }
 
+        public static partial void MapToDerivedExisting(global::Riok.Mapperly.IntegrationTests.Models.ExistingObjectBase source, global::Riok.Mapperly.IntegrationTests.Models.ExistingObjectBase target)
+        {
+            switch (source, target)
+            {
+                case (global::Riok.Mapperly.IntegrationTests.Models.ExistingObjectTypeA source1, global::Riok.Mapperly.IntegrationTests.Models.ExistingObjectTypeA target1):
+                    target1.ValueA = DirectInt(source1.ValueA);
+                    target1.Value = DirectInt(source1.Value);
+                    break;
+                case (global::Riok.Mapperly.IntegrationTests.Models.ExistingObjectTypeB source1, global::Riok.Mapperly.IntegrationTests.Models.ExistingObjectTypeB target1):
+                    target1.ValueB = DirectInt(source1.ValueB);
+                    target1.Value = DirectInt(source1.Value);
+                    break;
+                default:
+                    throw new System.ArgumentException($"Cannot map {source.GetType()} to {target.GetType()} as there is no known derived type mapping", nameof(source));
+            }
+        }
+
         public static partial global::Riok.Mapperly.IntegrationTests.Dto.TestEnumDtoByName MapToEnumDtoByName(global::Riok.Mapperly.IntegrationTests.Models.TestEnum v)
         {
             return v switch