Dill, John wrote:

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So e.g. list1 is always instantiated with a reference type,

to what? the original type, or the add_value processed type?

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and thus it also stores the arguments as references.

I still think that those types are processed by add_value before being used. The bind_t L template parameter is instantiated with a list of add_value modified types through list_av_N in the bind calls, which leads me to believe that the listN represented by l_ object in bind_t has types of either value<T>, reference_wrapper<T>, or other bind_t structures. So are the types stored in listN (A1, A2, ... ) ever the original type or the original reference type? Or are they always add_value<T> processed?

The types in l_ are always add_value processed, the types in the other listN that stores references to the arguments at the call site are not. In bind(f, a1, a2)(b1, b2); bind(f, a1, a2) creates a list2 that holds the values of a1 and a2, add_value-processed. The call (b1, b2) creates a list2<B1&, B2&> that holds references to b1 and b2. These are all implementation details. I don't see why you seem so worried about them. In particular, add_value is only present because of the need to support MSVC 6. On a compiler that supports partial specialization, it's possible to use an unadorned list2<A1, A2> as l_. Many other implementation variations are also possible.