find types implementing generic interface

gistfile1.cs

private readonly static Type messageHandlerOpenGenericType = typeof(IMessageHandler<>);

        public static IEnumerable<Type> WhereMessageHandlerType(this IEnumerable<Type> types) {
            return types.Where(x => x.IsClass &&
                                   !x.IsAbstract &&
                                    x.GetInterfaces().Any(i => i.IsGenericType &&
                                                               i.GetGenericTypeDefinition() == messageHandlerOpenGenericType));
        }