cet-is » art

In order to provide a const-qualified handle to a service--i.e. the returned handle provides access to const-only interface--users should be able to type ServiceHandle<T const>. However, doing so triggers a compile-time error due to a missing specialization for art::detail::ServiceHelper<T const>. In order to provide this facility, the const-ness of the provided template argument should be removed before being presented as an argument to art::detail::ServiceHelper.