- fix factories of open generic registration

LightweightIocContainer/Factories/TypedFactory.cs

@@ -75,6 +75,26 @@ public class TypedFactory<TFactory> : TypedFactoryBase<TFactory>, ITypedFactory<
 
             MethodBuilder methodBuilder = typeBuilder.DefineMethod(createMethod.Name, MethodAttributes.Public | MethodAttributes.Virtual, 
                 createMethod.ReturnType, (from arg in args select arg.ParameterType).ToArray());
+
+            if (createMethod.IsGenericMethod)
+            {
+                Type[] genericArguments = createMethod.GetGenericMethodDefinition().GetGenericArguments();
+                string[] genericArgumentNames = genericArguments.Select(a => a.Name).ToArray();
+                
+                GenericTypeParameterBuilder[] genericParameters = methodBuilder.DefineGenericParameters(genericArgumentNames);
+
+                foreach (GenericTypeParameterBuilder genericParameter in genericParameters)
+                {
+                    Type genericType = genericArguments.First(a => a.Name == genericParameter.Name);
+                    genericParameter.SetGenericParameterAttributes(genericType.GenericParameterAttributes);
+                    
+                    genericParameter.SetInterfaceConstraints(genericType.GetGenericParameterConstraints().Where(c => c.IsInterface).ToArray());
+                    Type? typeConstraint = genericType.GetGenericParameterConstraints().FirstOrDefault(c => !c.IsInterface);
+                    if (typeConstraint is not null)
+                        genericParameter.SetBaseTypeConstraint(typeConstraint);
+                }
+            }
+            
             typeBuilder.DefineMethodOverride(methodBuilder, createMethod);
 
             ILGenerator generator = methodBuilder.GetILGenerator();

LightweightIocContainer/Registrations/OpenGenericRegistration.cs

@@ -42,7 +42,16 @@ internal class OpenGenericRegistration : RegistrationBase, IOpenGenericRegistrat
             
         base.Validate();
     }
+
+    protected override void ValidateFactory()
+    {
+        if (Factory == null)
+            return;
         
+        if (Factory.CreateMethods.All(c => c.ReturnType.Name != InterfaceType.Name))
+            throw new InvalidFactoryRegistrationException($"No create method that can create {InterfaceType}.");
+    }
+
     public override bool Equals(object? obj) => obj is OpenGenericRegistration openGenericRegistration &&
                                                 base.Equals(obj) &&
                                                 ImplementationType == openGenericRegistration.ImplementationType;

Test.LightweightIocContainer/OpenGenericRegistrationTest.cs

@@ -14,19 +14,36 @@ namespace Test.LightweightIocContainer;
 public class OpenGenericRegistrationTest
 {
     private IocContainer _iocContainer;
+
+    [UsedImplicitly]
+    public interface IConstraint
+    {
+        
+    }
+    
+    [UsedImplicitly]
+    public class Constraint : IConstraint
+    {
+        
+    }
         
     [UsedImplicitly]
     [SuppressMessage("ReSharper", "UnusedTypeParameter")]
-    public interface ITest<T>
+    public interface ITest<T> where T : IConstraint, new()
     {
             
     }
         
     [UsedImplicitly]
-    public class Test<T> : ITest<T>
+    public class Test<T> : ITest<T> where T : IConstraint, new()
     {
             
     }
+    
+    public interface ITestFactory
+    {
+        ITest<T> Create<T>() where T : IConstraint, new();
+    }
 
     [SetUp]
     public void SetUp() => _iocContainer = new IocContainer();
@@ -39,7 +56,7 @@ public class OpenGenericRegistrationTest
     {
         _iocContainer.Register(r => r.AddOpenGenerics(typeof(ITest<>), typeof(Test<>)));
 
-        ITest<int> test = _iocContainer.Resolve<ITest<int>>();
+        ITest<Constraint> test = _iocContainer.Resolve<ITest<Constraint>>();
         Assert.NotNull(test);
     }
 
@@ -48,10 +65,10 @@ public class OpenGenericRegistrationTest
     {
         _iocContainer.Register(r => r.AddOpenGenerics(typeof(ITest<>), typeof(Test<>), Lifestyle.Singleton));
 
-        ITest<int> test = _iocContainer.Resolve<ITest<int>>();
+        ITest<Constraint> test = _iocContainer.Resolve<ITest<Constraint>>();
         Assert.NotNull(test);
 
-        ITest<int> secondTest = _iocContainer.Resolve<ITest<int>>();
+        ITest<Constraint> secondTest = _iocContainer.Resolve<ITest<Constraint>>();
         Assert.NotNull(secondTest);
             
         Assert.AreEqual(test, secondTest);
@@ -65,4 +82,13 @@ public class OpenGenericRegistrationTest
     [Test]
     public void TestRegisterNonOpenGenericTypeWithOpenGenericsFunctionThrowsException() =>
         Assert.Throws<InvalidRegistrationException>(() => _iocContainer.Register(r => r.AddOpenGenerics(typeof(int), typeof(int))));
+
+    [Test]
+    public void TestRegisterFactoryOfOpenGenericType()
+    {
+        _iocContainer.Register(r => r.AddOpenGenerics(typeof(ITest<>), typeof(Test<>)).WithFactory<ITestFactory>());
+        ITestFactory testFactory = _iocContainer.Resolve<ITestFactory>();
+        ITest<Constraint> test = testFactory.Create<Constraint>();
+        Assert.IsInstanceOf<ITest<Constraint>>(test);
+    }
 }