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131
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1 // { dg-do run { target c++17 } }
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2 // { dg-options "-fconcepts" }
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111
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3
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4 #include <cassert>
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5
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6 template<typename T>
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7 concept bool C() { return __is_class(T); }
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8
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9 template<typename T>
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10 concept bool D() { return C<T>() && __is_empty(T); }
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11
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12 struct X { } x;
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13 struct Y { int n; } y;
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14
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15 template<typename T> void g(T) { } // #1
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16 template<C T> void g(T) { } // #2
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17 template<D T> void g(T) { } // #3
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18
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19 int called;
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20
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21 template<> void g(int) { called = 1; } // Specialization of #1
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22 template<> void g<X>(X) { called = 2; } // Specialization of #3
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23 template<> void g(Y) { called = 3; } // Specialization of #2
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24
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25 int main() {
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26 g(0);
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27 assert(called == 1);
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28 g(x);
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29 assert(called == 2);
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30 g(y);
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31 assert(called == 3);
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32 }
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