[DNM] Add failing test for generic wrappers in extension members

tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionMembers/Entity.cs

@@ -5,6 +5,6 @@ public class Entity
     {
         public int Id { get; set; }
         public string Name { get; set; } = string.Empty;
-    }    
+    }
 }
 #endif

tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionMembers/EntityExtensions.cs

@@ -23,6 +23,15 @@ public static class EntityExtensions
             [Projectable]
             public int Multiply(int factor) => e.Id * factor;
         }
+
+        extension (GenericWrapper<Entity> w)
+        {
+            /// <summary>
+            /// Extension member method that multiplies the wrapped entity's ID by a factor.
+            /// </summary>
+            [Projectable]
+            public int MultiplyWrapped(int factor) => w.Wrapped.Id * factor;
+        }
     }
 
     public static class IntExtensions

tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionMembers/ExtensionMemberTests.ExtensionMemberMethodWithParameterOnWrappedEntity.DotNet10_0.verified.txt

@@ -0,0 +1,2 @@
+SELECT [e].[Id] * 10
+FROM [Entity] AS [e]

tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionMembers/ExtensionMemberTests.cs

@@ -37,6 +37,18 @@ public Task ExtensionMemberMethodWithParameterOnEntity()
 
             return Verifier.Verify(query.ToQueryString());
         }
+
+        [Fact]
+        public Task ExtensionMemberMethodWithParameterOnWrappedEntity()
+        {
+            using var dbContext = new SampleDbContext<Entity>();
+
+            var query = dbContext.Set<Entity>()
+                .Select(x => new GenericWrapper<Entity> { Wrapped = x })
+                .Select(w => w.MultiplyWrapped(10));
+
+            return Verifier.Verify(query.ToQueryString());
+        }
     }
 }
 #endif

tests/EntityFrameworkCore.Projectables.FunctionalTests/ExtensionMembers/GenericWrapper.cs

@@ -0,0 +1,9 @@
+#if NET10_0_OR_GREATER
+namespace EntityFrameworkCore.Projectables.FunctionalTests.ExtensionMembers
+{
+    public sealed class GenericWrapper<T>
+    {
+        public required T Wrapped { get; set; }
+    }
+}
+#endif

tests/EntityFrameworkCore.Projectables.Generator.Tests/ExtensionMemberTests.ExtensionMemberOnGenericType.verified.txt

@@ -0,0 +1,17 @@
+// <auto-generated/>
+#nullable disable
+using System;
+using EntityFrameworkCore.Projectables;
+using Foo;
+
+namespace EntityFrameworkCore.Projectables.Generated
+{
+    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
+    static class Foo_EntityExtensions_TimesHundred
+    {
+        static global::System.Linq.Expressions.Expression<global::System.Func<global::Foo.Wrapper<global::Foo.Entity>, int>> Expression()
+        {
+            return (global::Foo.Wrapper<global::Foo.Entity> @this) => @this.Wrapped.Value * 100;
+        }
+    }
+}

tests/EntityFrameworkCore.Projectables.Generator.Tests/ExtensionMemberTests.cs

@@ -17,10 +17,10 @@ public Task ExtensionMemberProperty()
 using EntityFrameworkCore.Projectables;
 
 namespace Foo {
-    class Entity { 
+    class Entity {
         public int Id { get; set; }
     }
-    
+
     static class EntityExtensions {
         extension(Entity e) {
             [Projectable]
@@ -46,10 +46,10 @@ public Task ExtensionMemberMethod()
 using EntityFrameworkCore.Projectables;
 
 namespace Foo {
-    class Entity { 
+    class Entity {
         public int Id { get; set; }
     }
-    
+
     static class EntityExtensions {
         extension(Entity e) {
             [Projectable]
@@ -75,10 +75,10 @@ public Task ExtensionMemberMethodWithParameters()
 using EntityFrameworkCore.Projectables;
 
 namespace Foo {
-    class Entity { 
+    class Entity {
         public int Id { get; set; }
     }
-    
+
     static class EntityExtensions {
         extension(Entity e) {
             [Projectable]
@@ -127,11 +127,11 @@ public Task ExtensionMemberWithMemberAccess()
 using EntityFrameworkCore.Projectables;
 
 namespace Foo {
-    class Entity { 
+    class Entity {
         public int Id { get; set; }
         public string Name { get; set; }
     }
-    
+
     static class EntityExtensions {
         extension(Entity e) {
             [Projectable]
@@ -277,7 +277,39 @@ static class EntityExtensions {
         Assert.Empty(result.Diagnostics);
         Assert.Single(result.GeneratedTrees);
 
+        return Verifier.Verify(result.GeneratedTrees[0].ToString());
+    }
+    [Fact]
+    public Task ExtensionMemberOnGenericType()
+    {
+        var compilation = CreateCompilation(@"
+using System;
+using EntityFrameworkCore.Projectables;
+
+namespace Foo {
+    class Entity {
+        public int Value { get; set; }
+    }
+
+    class Wrapper<T> {
+        public T Wrapped { get; set; }
+    }
+
+    static class EntityExtensions {
+        extension(Wrapper<Entity> e) {
+            [Projectable]
+            public int TimesHundred => e.Wrapped.Value * 100;
+        }
+    }
+}
+");
+
+        var result = RunGenerator(compilation);
+
+        Assert.Empty(result.Diagnostics);
+        Assert.Single(result.GeneratedTrees);
+
         return Verifier.Verify(result.GeneratedTrees[0].ToString());
     }
 #endif
-}
+}