### 2571. §[map.modifiers]/2 imposes nonsensical requirement on `insert(InputIterator, InputIterator)`

**Section:** 24.4.4.4 [map.modifiers] **Status:** C++17
**Submitter:** Tim Song **Opened:** 2015-12-12 **Last modified:** 2017-07-30 20:15:43 UTC

**Priority: **0

**View all other** issues in [map.modifiers].

**View all issues with** C++17 status.

**Discussion:**

The initial paragraphs of 24.4.4.4 [map.modifiers] currently read:

template <class P> pair<iterator, bool> insert(P&& x);
template <class P> iterator insert(const_iterator position, P&& x);
template <class InputIterator>
void insert(InputIterator first, InputIterator last);

-1- *Effects*: The first form is equivalent to `return emplace(std::forward<P>(x))`. The second form is
equivalent to `return emplace_hint(position, std::forward<P>(x))`.

-2- *Remarks*: These signatures shall not participate in overload resolution unless `std::is_constructible<value_type,
P&&>::value` is `true`.

Clearly, p2's requirement makes no sense for `insert(InputIterator, InputIterator)` - it doesn't even have
a template parameter called `P`.

This paragraph used to have text saying "The signature taking `InputIterator` parameters does not require
`CopyConstructible` of either `key_type` or `mapped_type` if the dereferenced `InputIterator`
returns a non-`const` rvalue `pair<key_type,mapped_type>`. Otherwise `CopyConstructible` is
required for both `key_type` and `mapped_type`", but that was removed by LWG 2005, whose PR
was written as if that overload didn't exist in the text.

It looks like the text addressing this overload is redundant to the requirements on `a.insert(i, j)` in Table 102
that `value_type` be `EmplaceConstructible` from `*i`. If so, then the signature should just be
deleted from this section.

*[2016-02, Issues Telecon]*

P0; move to Tentatively Ready.

**Proposed resolution:**

This wording is relative to N4567.

Edit 24.4.4.4 [map.modifiers] as indicated:

template <class P> pair<iterator, bool> insert(P&& x);
template <class P> iterator insert(const_iterator position, P&& x);
~~template <class InputIterator>
void insert(InputIterator first, InputIterator last);~~

-1- *Effects*: The first form is equivalent to `return emplace(std::forward<P>(x))`. The second form is
equivalent to `return emplace_hint(position, std::forward<P>(x))`.

-2- *Remarks*: These signatures shall not participate in overload resolution unless `std::is_constructible<value_type,
P&&>::value` is `true`.