#include <iostream>
#include <string>
using namespace std;
extern void* enabler;
 
template <typename STR, std::enable_if_t<sizeof(decltype(typename std::remove_all_extents<STR>::type()[0])) == 1> *& = enabler>
void hoge(const STR&)
{
cout << "v1";
}
 
 
template <typename STR, std::enable_if_t<sizeof(decltype(typename std::remove_all_extents<STR>::type()[0])) != 1> *& = enabler>
void hoge(const STR&)
{
cout << "v2";
}
 
int main() {
	std::string s;
	hoge(s); 
	return 0;
}

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