From: marc.glisse@googlemail.com   
      
   Daniel Krügler  wrote:   
      
   > On 2012-10-09 15:16, Gennadiy Rozental wrote:   
   >> On Tuesday, October 9, 2012 12:30:03 AM UTC-4, Daniel Krügler wrote:   
   >>> Am 09.10.2012 00:48, schrieb Gennadiy Rozental:   
   >>>> Any workarounds?   
   >>> The usual technique is to specify a function of the form T&& and to   
   >>> constrain it accordingly. E.g.   
   >>> #include    
   >>> #include    
   >>   
   >>> template   
   >>> struct is_vector : std::false_type {};   
   >>> template   
   >>> struct is_vector> : std::true_type {};   
   >>   
   >> While we on the subject, why doesn't standard type traits provide   
   >> this?   
   >   
   > I don't think that this trait should be standardized, because it is   
   > neither very complicated to write, nor do I see any general pattern in   
   > it.   
      
   I guess this version is very slightly more general:   
      
   templateclass U>   
   struct is:std::false_type{};   
      
   templateclass U>   
   struct is,U>:std::true_type{};   
      
   static_assert(is,std::vector>::value,"error");   
   static_assert(!is,std::vector>::value,"error");   
      
   I agree with your post, I just wanted to mention this because I find it   
   nice that variadic templates allow it. It gets harder if we want 'is' to   
   act like is_same for non-template parameters U though :-(   
      
      
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