This should do the same changes for std::insert_iterator, but it
currently crashes the compiler (PR 93907). I am not committing this
yet.
commit 2db20402125e6136d6768598f5974e917b2622c6
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Mon Feb 24 15:50:59 2020 +0000
libstdc++: Add missing bits of P0896R4 pertaining to insert_iterator (PR 93884)
This completes the fix for PR 93884. In order to use ranges::iterator_t
in std::insert_iterator the definition of ranges::iterator_t and
ranges::begin need to be moved, to avoid a circular dependency between
<bits/stl_iterator.h> and <bits/range_access.h>.
As noted in a FIXME comment, the std::inserter function has the wrong
signature because LWG issue 561 was never implemented. That is tracked
by PR 93904.
PR libstdc++/93884
* include/bits/iterator_concepts.h (__detail::__maybe_borrowed_range)
(__cust_access::_Begin, ranges::iterator_t): Move from ...
* include/bits/range_access.h: ... here.
* include/bits/stl_iterator.h (insert_iterator, inserter): Implement
C++20 changes from P0896R4.
* testsuite/24_iterators/insert_iterator/pr93884.cc: New test.
diff --git a/libstdc++-v3/include/bits/iterator_concepts.h b/libstdc++-v3/include/bits/iterator_concepts.h
index 08e622259b4..ae0c207d0d9 100644
--- a/libstdc++-v3/include/bits/iterator_concepts.h
+++ b/libstdc++-v3/include/bits/iterator_concepts.h
@@ -835,6 +835,90 @@ namespace ranges
struct default_sentinel_t { };
inline constexpr default_sentinel_t default_sentinel{};
+namespace ranges
+{
+ template<typename _Tp>
+ extern const bool enable_borrowed_range;
+
+ namespace __detail
+ {
+ // Part of the constraints of ranges::borrowed_range
+ template<typename _Tp>
+ concept __maybe_borrowed_range
+ = is_lvalue_reference_v<_Tp>
+ || enable_borrowed_range<remove_cvref_t<_Tp>>;
+ } // namespace __detail
+
+ namespace __cust_access
+ {
+ template<typename _Tp>
+ constexpr decay_t<_Tp>
+ __decay_copy(_Tp&& __t)
+ noexcept(is_nothrow_convertible_v<_Tp, decay_t<_Tp>>)
+ { return std::forward<_Tp>(__t); }
+
+ template<typename _Tp>
+ concept __member_begin = requires(_Tp& __t)
+ {
+ __t.begin();
+ requires input_or_output_iterator<decay_t<decltype(__t.begin())>>;
+ };
+
+ void begin(auto&) = delete;
+ void begin(const auto&) = delete;
+
+ template<typename _Tp>
+ concept __adl_begin
+ = std::__detail::__class_or_enum<remove_reference_t<_Tp>>
+ && requires(_Tp& __t)
+ {
+ begin(__t);
+ requires input_or_output_iterator<decay_t<decltype(begin(__t))>>;
+ };
+
+ struct _Begin
+ {
+ private:
+ template<typename _Tp>
+ static constexpr bool
+ _S_noexcept()
+ {
+ if constexpr (is_array_v<remove_reference_t<_Tp>>)
+ return true;
+ else if constexpr (__member_begin<_Tp>)
+ return noexcept(__decay_copy(std::declval<_Tp&>().begin()));
+ else
+ return noexcept(__decay_copy(begin(std::declval<_Tp&>())));
+ }
+
+ public:
+ template<__detail::__maybe_borrowed_range _Tp>
+ requires is_array_v<remove_reference_t<_Tp>> || __member_begin<_Tp>
+ || __adl_begin<_Tp>
+ constexpr auto
+ operator()(_Tp&& __t) const noexcept(_S_noexcept<_Tp>())
+ {
+ if constexpr (is_array_v<remove_reference_t<_Tp>>)
+ {
+ static_assert(is_lvalue_reference_v<_Tp>);
+ using _Up = remove_all_extents_t<remove_reference_t<_Tp>>;
+ static_assert(sizeof(_Up) != 0, "not array of incomplete type");
+ return __t + 0;
+ }
+ else if constexpr (__member_begin<_Tp>)
+ return __t.begin();
+ else
+ return begin(__t);
+ }
+ };
+ } // namespace __cust_access
+
+ template<typename _Tp>
+ using iterator_t
+ = decltype(__cust_access::_Begin{}(std::declval<_Tp&>()));
+
+} // namespace ranges
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // C++20 library concepts
diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h
index 8b276fd6625..7ae08f58f67 100644
--- a/libstdc++-v3/include/bits/range_access.h
+++ b/libstdc++-v3/include/bits/range_access.h
@@ -359,13 +359,6 @@ namespace ranges
template<typename _Tp, bool _MaxDiff = same_as<_Tp, __max_diff_type>>
using __make_unsigned_like_t
= conditional_t<_MaxDiff, __max_size_type, make_unsigned_t<_Tp>>;
-
- // Part of the constraints of ranges::borrowed_range
- template<typename _Tp>
- concept __maybe_borrowed_range
- = is_lvalue_reference_v<_Tp>
- || enable_borrowed_range<remove_cvref_t<_Tp>>;
-
} // namespace __detail
namespace __cust_access
@@ -373,64 +366,6 @@ namespace ranges
using std::ranges::__detail::__maybe_borrowed_range;
using std::__detail::__class_or_enum;
- template<typename _Tp>
- constexpr decay_t<_Tp>
- __decay_copy(_Tp&& __t)
- noexcept(is_nothrow_convertible_v<_Tp, decay_t<_Tp>>)
- { return std::forward<_Tp>(__t); }
-
- template<typename _Tp>
- concept __member_begin = requires(_Tp& __t)
- {
- { __decay_copy(__t.begin()) } -> input_or_output_iterator;
- };
-
- void begin(auto&) = delete;
- void begin(const auto&) = delete;
-
- template<typename _Tp>
- concept __adl_begin = __class_or_enum<remove_reference_t<_Tp>>
- && requires(_Tp& __t)
- {
- { __decay_copy(begin(__t)) } -> input_or_output_iterator;
- };
-
- struct _Begin
- {
- private:
- template<typename _Tp>
- static constexpr bool
- _S_noexcept()
- {
- if constexpr (is_array_v<remove_reference_t<_Tp>>)
- return true;
- else if constexpr (__member_begin<_Tp>)
- return noexcept(__decay_copy(std::declval<_Tp&>().begin()));
- else
- return noexcept(__decay_copy(begin(std::declval<_Tp&>())));
- }
-
- public:
- template<__maybe_borrowed_range _Tp>
- requires is_array_v<remove_reference_t<_Tp>> || __member_begin<_Tp>
- || __adl_begin<_Tp>
- constexpr auto
- operator()(_Tp&& __t) const noexcept(_S_noexcept<_Tp>())
- {
- if constexpr (is_array_v<remove_reference_t<_Tp>>)
- {
- static_assert(is_lvalue_reference_v<_Tp>);
- using _Up = remove_all_extents_t<remove_reference_t<_Tp>>;
- static_assert(sizeof(_Up) != 0, "not array of incomplete type");
- return __t + 0;
- }
- else if constexpr (__member_begin<_Tp>)
- return __t.begin();
- else
- return begin(__t);
- }
- };
-
template<typename _Tp>
concept __member_end = requires(_Tp& __t)
{
@@ -888,9 +823,6 @@ namespace ranges
concept borrowed_range
= range<_Tp> && __detail::__maybe_borrowed_range<_Tp>;
- template<typename _Tp>
- using iterator_t = decltype(ranges::begin(std::declval<_Tp&>()));
-
template<range _Range>
using sentinel_t = decltype(ranges::end(std::declval<_Range&>()));
diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index caaa8c483b8..c332343d11b 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -704,19 +704,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
class insert_iterator
: public iterator<output_iterator_tag, void, void, void, void>
{
+#if __cplusplus <= 201703L
+ typedef typename _Container::iterator _Iter;
+#else
+ using _Iter = ranges::iterator_t<_Container>;
+#endif
+
protected:
+#if __cplusplus <= 201703L
_Container* container;
- typename _Container::iterator iter;
+ _Iter iter;
+#else
+ _Container* container = nullptr;
+ _Iter iter = _Iter();
+#endif
public:
/// A nested typedef for the type of whatever container you used.
typedef _Container container_type;
+#if __cplusplus > 201703L
+ using difference_type = ptrdiff_t;
+
+ insert_iterator() = default;
+#endif
+
/**
* The only way to create this %iterator is with a container and an
* initial position (a normal %iterator into the container).
*/
- insert_iterator(_Container& __x, typename _Container::iterator __i)
+ insert_iterator(_Container& __x, _Iter __i)
: container(std::__addressof(__x)), iter(__i) {}
/**
@@ -782,6 +799,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
insert_iterator&
operator++(int)
{ return *this; }
+
+#if __cplusplus >= 201703L
+ template<typename _Cont>
+ friend insert_iterator<_Cont>
+ inserter(_Cont&, typename insert_iterator<_Cont>::_Iter);
+#endif
};
/**
@@ -796,6 +819,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* template parameter deduction, making the compiler match the correct
* types for you.
*/
+#if __cplusplus <= 201703L
+ // FIXME: This version should not exist (PR 93904)
template<typename _Container, typename _Iterator>
inline insert_iterator<_Container>
inserter(_Container& __x, _Iterator __i)
@@ -803,6 +828,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return insert_iterator<_Container>(__x,
typename _Container::iterator(__i));
}
+#else
+ template<typename _Container>
+ inline insert_iterator<_Container>
+ inserter(_Container& __x, typename insert_iterator<_Container>::_Iter __i)
+ {
+ return insert_iterator<_Container>(__x, __i);
+ }
+#endif
// @} group iterators
diff --git a/libstdc++-v3/testsuite/24_iterators/insert_iterator/pr93884.cc b/libstdc++-v3/testsuite/24_iterators/insert_iterator/pr93884.cc
new file mode 100644
index 00000000000..e0949e64152
--- /dev/null
+++ b/libstdc++-v3/testsuite/24_iterators/insert_iterator/pr93884.cc
@@ -0,0 +1,44 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { target c++2a } }
+
+#include <iterator>
+#include <algorithm>
+#include <set>
+#include <testsuite_hooks.h>
+
+namespace ranges = std::ranges;
+namespace views = std::views;
+
+void
+test01()
+{
+ auto s = std::set<int>{};
+ auto i = views::iota(0, 10);
+ auto o = std::inserter(s, s.begin());
+ static_assert(std::output_iterator<decltype(o), int>);
+ ranges::copy(i, o);
+ VERIFY( ranges::equal(s, i) );
+}
+
+int
+main()
+{
+ test01();
+}
