[Bug libstdc++/105717] New: [9/10/11/12/13 Regression] cannot create unordered_map from range of types convertible to value_type

[Bug libstdc++/105717] New: [9/10/11/12/13 Regression] cannot create unordered_map from range of types convertible to value_type

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105717

            Bug ID: 105717
           Summary: [9/10/11/12/13 Regression] cannot create unordered_map
                    from range of types convertible to value_type
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
                CC: unassigned at gcc dot gnu.org
  Target Milestone: ---

+++ This bug was initially created as a clone of Bug #56112 +++

François observed that I fixed construction for PR 56112, but we still don't
support insertion of such types:

#include <unordered_map>
#include <utility>
#include <assert.h>

struct Key
{
  explicit Key(const int* p) : value(p) { }
  ~Key() { value = nullptr; }

  bool operator==(const Key& k) const
  { return *value == *k.value; }

  const int* value;
};

struct hash
{
  std::size_t operator()(const Key& k) const noexcept
  { return *k.value; }
};

struct S
{
  static int _count;

  int value;
  operator std::pair<const Key, int>() const
  {
    ++_count;
    return { Key(&value), value };
  }
};

int S::_count = 0;

int main()
{
    S s[1] = { {2} };
    std::unordered_map<Key, int, hash> m(s, s + 1);
    assert( S::_count == 1 );

    std::unordered_multimap<Key, int, hash> mm(s, s + 1);
    assert( S::_count == 2 );

    m.insert(s, s + 1);
    assert( S::_count == 3 );

    mm.insert(s, s + 1);
    assert( S::_count == 4 );
}


This worked in 4.7

[Bug libstdc++/105717] [9/10/11/12/13 Regression] cannot create unordered_map from range of types convertible to value_type

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105717

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|unassigned at gcc dot gnu.org      |
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-05-24

[Bug libstdc++/105717] [9/10/11/12/13 Regression] cannot create unordered_map from range of types convertible to value_type

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105717

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.4

[Bug libstdc++/105717] [10/11/12/13 Regression] cannot create unordered_map from range of types convertible to value_type

[fdumont at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105717

François Dumont <fdumont at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
   Target Milestone|10.4                        |13.0
                 CC|                            |fdumont at gcc dot gnu.org
         Resolution|---                         |FIXED
           Assignee|unassigned at gcc dot gnu.org      |fdumont at gcc dot gnu.org

--- Comment #1 from François Dumont <fdumont at gcc dot gnu.org> ---
    libstdc++: [_Hashtable] Insert range of types convertible to value_type PR
105717

    Fix insertion of range of instances convertible to value_type.

    libstdc++-v3/ChangeLog:

            PR libstdc++/105717
            * include/bits/hashtable_policy.h (_ConvertToValueType): New.
            * include/bits/hashtable.h (_Hashtable<>::_M_insert_unique_aux):
New.
            (_Hashtable<>::_M_insert(_Arg&&, const _NodeGenerator&,
true_type)): Use latters.
            (_Hashtable<>::_M_insert(_Arg&&, const _NodeGenerator&,
false_type)): Likewise.
            (_Hashtable(_InputIterator, _InputIterator, size_type, const
_Hash&, const _Equal&,
            const allocator_type&, true_type)): Use this.insert range.
            (_Hashtable(_InputIterator, _InputIterator, size_type, const
_Hash&, const _Equal&,
            const allocator_type&, false_type)): Use _M_insert.
            * testsuite/23_containers/unordered_map/cons/56112.cc: Check how
many times conversion
            is done.
            * testsuite/23_containers/unordered_map/insert/105717.cc: New test.
            * testsuite/23_containers/unordered_set/insert/105717.cc: New test.