libstdc++-v3/testsuite/23_containers/unordered_map/cons/default.cc

   1 // { dg-do compile { target c++11 } }
   2 #include <unordered_map>
   3
   4 static_assert( std::is_default_constructible<std::unordered_map<int, int>>{}, "" );
   5
   6 template<typename T>
   7   struct NoDefaultConsAlloc
   8   {
   9     using value_type = T;
  10
  11     NoDefaultConsAlloc(int) noexcept { }
  12
  13     template<typename U>
  14       NoDefaultConsAlloc(const NoDefaultConsAlloc<U>&) { }
  15
  16     T *allocate(std::size_t n)
  17     { return std::allocator<T>().allocate(n); }
  18
  19     void deallocate(T *p, std::size_t n)
  20     { std::allocator<T>().deallocate(p, n); }
  21
  22     bool operator==(const NoDefaultConsAlloc&) const { return true; }
  23     bool operator!=(const NoDefaultConsAlloc&) const { return false; }
  24   };
  25
  26 using Map = std::unordered_map<int, int, std::hash<int>, std::equal_to<int>,
  27                                NoDefaultConsAlloc<std::pair<const int, int>>>;
  28 static_assert( ! std::is_default_constructible<Map>{}, "PR libstdc++/100863" );
  29
  30 struct Hash : std::hash<int> { Hash(int) { } };
  31 using Map2 = std::unordered_map<int, int, Hash>;
  32 static_assert( ! std::is_default_constructible<Map2>{}, "PR libstdc++/100863" );
  33
  34 struct Equal : std::equal_to<int> { Equal(int) { } };
  35 using Map3 = std::unordered_map<int, int, std::hash<int>, Equal>;
  36 static_assert( ! std::is_default_constructible<Map3>{}, "PR libstdc++/100863" );
  37
  38 // PR libstdc++/101583
  39 // verify non-default ctors can still be used
  40 using Map4 = std::unordered_map<int, int, Hash, Equal,
  41                                 NoDefaultConsAlloc<std::pair<const int, int>>>;
  42 Hash h(1);
  43 Equal eq(1);
  44 Map4::allocator_type a(1);
  45 Map4 m{1, h, eq, a};
  46 Map4 m2{m.begin(), m.end(), m.size(), h, eq, a};
  47 Map4 m3{{{1,1}, {2,2}, {3,3}}, 3, h, eq, a};
  48 Map4 m4{m};
  49 Map4 m5{m, a};
  50 Map4 m6{std::move(m)};
  51 Map4 m7{std::move(m6), a};