From 268cf8a134dabb05c9f878b76ccda30f28ae2e0b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 24 Feb 2026 18:41:08 +0000
Subject: [PATCH 1/2] Initial plan


From a1e7961e49b75fd54eddd1a22945404b44b57f35 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 24 Feb 2026 18:44:16 +0000
Subject: [PATCH 2/2] Add test for Expression source with non-Expression
 destination validation

Co-authored-by: BlaiseD <7595209+BlaiseD@users.noreply.github.com>
---
 .../TypeMappingsManagerTest.cs                | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/TypeMappingsManagerTest.cs b/tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/TypeMappingsManagerTest.cs
index 4972038..1eb3c0e 100644
--- a/tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/TypeMappingsManagerTest.cs
+++ b/tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/TypeMappingsManagerTest.cs
@@ -208,6 +208,28 @@ public void AddTypeMapping_DuplicateMapping_DoesNotAddAgain()
             Assert.Equal(countAfterFirst, manager.TypeMappings.Count);
         }
 
+        [Fact]
+        public void AddTypeMapping_ExpressionSourceNonExpressionDest_ThrowsArgumentException()
+        {
+            // Arrange
+            var config = ConfigurationHelper.GetMapperConfiguration(cfg =>
+            {
+                cfg.CreateMap<SourceModel, DestModel>();
+            });
+            var manager = new TypeMappingsManager(
+                config,
+                typeof(Func<SourceModel, bool>),
+                typeof(Func<DestModel, bool>));
+
+            // Act & Assert
+            var exception = Assert.Throws<ArgumentException>(() =>
+                manager.AddTypeMapping(
+                    typeof(Expression<Func<SourceChild, bool>>),
+                    typeof(Func<DestChild, bool>)));
+
+            Assert.Contains("Invalis type mappings", exception.Message);
+        }
+
         [Fact]
         public void AddTypeMapping_ListTypes_AddsUnderlyingTypeMappings()
         {