1 namespace std {
2   template<typename> struct mersenne_twister_engine {
3     friend bool operator==(const mersenne_twister_engine &,
4                            const mersenne_twister_engine &) {
5       return false;
6     }
7   };
8   struct random_device {
9     mersenne_twister_engine<int> mt; // require complete type
10   };
11 }
12 
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