//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// <unordered_set>

// template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
//           class Alloc = allocator<Value>>
// class unordered_multiset

// iterator erase(const_iterator p)

#include <unordered_set>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

struct TemplateConstructor
{
    template<typename T>
    TemplateConstructor (const T&) {}
};

bool operator==(const TemplateConstructor&, const TemplateConstructor&) { return false; }
struct Hash { std::size_t operator() (const TemplateConstructor &) const { return 0; } };

int main(int, char**)
{
    {
        typedef std::unordered_multiset<int> C;
        typedef int P;
        P a[] =
        {
            P(1),
            P(2),
            P(3),
            P(4),
            P(1),
            P(2)
        };
        C c(a, a + sizeof(a)/sizeof(a[0]));
        C::const_iterator i = c.find(2);
        C::const_iterator i_next = i;
        ++i_next;
        C::iterator j = c.erase(i);
        assert(j == i_next);

        assert(c.size() == 5);
        assert(c.count(1) == 2);
        assert(c.count(2) == 1);
        assert(c.count(3) == 1);
        assert(c.count(4) == 1);
    }
#if TEST_STD_VER >= 11
    {
        typedef std::unordered_multiset<int, std::hash<int>,
                                      std::equal_to<int>, min_allocator<int>> C;
        typedef int P;
        P a[] =
        {
            P(1),
            P(2),
            P(3),
            P(4),
            P(1),
            P(2)
        };
        C c(a, a + sizeof(a)/sizeof(a[0]));
        C::const_iterator i = c.find(2);
        C::const_iterator i_next = i;
        ++i_next;
        C::iterator j = c.erase(i);
        assert(j == i_next);
        assert(c.size() == 5);
        assert(c.count(1) == 2);
        assert(c.count(2) == 1);
        assert(c.count(3) == 1);
        assert(c.count(4) == 1);
    }
#endif
#if TEST_STD_VER >= 14
    {
    //  This is LWG #2059
        typedef TemplateConstructor T;
        typedef std::unordered_set<T, Hash> C;
        typedef C::iterator I;

        C m;
        T a{0};
        I it = m.find(a);
        if (it != m.end())
            m.erase(it);
    }
#endif

  return 0;
}