c++ - template template parameters and forwarding references -


suppose have following code:

template<typename t> class c {};  template <typename t, template <typename> class container> void dummyme(container<t>&&) {};  int main(int argc, char* argv[]) {     c<int> c;     dummyme(c);     return 0; }

which doesn't compile due first dummyme argument being rvalue-reference. explain me in standardese why template template parameters not getting along forwarding references , why in plain english.

p.s. i've stumbled on this , that questions not see real proofs in answers.

an answer link above , answer question assert container<t> can't counted template parameter. , see no reason why so. let's make example simpler:

template <template <typename=int> class container> void dummyme(container<>&&) {};

now have example identical following:

template <typename container> void dummyme(container&&) {};

but treated in different fashion. why? why container<>&& can't considered same thing template <typename=int> class container container&& typename container?

an answer link above , answer question assert container<t> can't counted template parameter

what or not template parameter not subject interpretation. defined in [temp.param]:

template-parameter:      type-parameter      parameter-declaration   type-parameter:      type-parameter-key ...(opt) identier (opt)     type-parameter-key identier(opt) = type-id      template < template-parameter-list > type-parameter-key ...(opt) identier(opt)     template < template-parameter-list > type-parameter-key identier(opt) = id-expression  type-parameter-key:      class     typename

it clear these production rules dummyme has 2 template parameters: typename t , template <typename> class container. identifiers name each of these parameters t , container. t names first parameter , container names second one. container<t> not identifier , names neither of two.


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