The standard requires that these deduction guides are constrained to
only accept a type that qualifies as an allocator for the second
templates argument.
libstdc++-v3/ChangeLog:
* include/bits/stl_deque.h: Add missing constraint on allocator
type in deduction guide.
* include/bits/stl_vector.h: Likewise.
* include/debug/deque: Likewise.
* include/debug/vector: Likewise.
* testsuite/23_containers/deque/cons/deduction_c++23.cc: Check
that deduction fails for a type which does not qualify as an
allocator.
* testsuite/23_containers/vector/cons/deduction_c++23.cc:
Likewise.
---
Tested x86_64-linux.
libstdc++-v3/include/bits/stl_deque.h | 2 +-
libstdc++-v3/include/bits/stl_vector.h | 2 +-
libstdc++-v3/include/debug/deque | 2 +-
libstdc++-v3/include/debug/vector | 2 +-
.../23_containers/deque/cons/deduction_c++23.cc | 14 ++++++++++++++
.../23_containers/vector/cons/deduction_c++23.cc | 14 ++++++++++++++
6 files changed, 32 insertions(+), 4 deletions(-)
create mode 100644
libstdc++-v3/testsuite/23_containers/deque/cons/deduction_c++23.cc
create mode 100644
libstdc++-v3/testsuite/23_containers/vector/cons/deduction_c++23.cc
diff --git a/libstdc++-v3/include/bits/stl_deque.h
b/libstdc++-v3/include/bits/stl_deque.h
index aebe865ffc1a..28f61d2ccd37 100644
--- a/libstdc++-v3/include/bits/stl_deque.h
+++ b/libstdc++-v3/include/bits/stl_deque.h
@@ -2414,7 +2414,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
#if __glibcxx_containers_ranges // C++ >= 23
template<ranges::input_range _Rg,
- typename _Alloc = allocator<ranges::range_value_t<_Rg>>>
+ __allocator_like _Alloc = allocator<ranges::range_value_t<_Rg>>>
deque(from_range_t, _Rg&&, _Alloc = _Alloc())
-> deque<ranges::range_value_t<_Rg>, _Alloc>;
#endif
diff --git a/libstdc++-v3/include/bits/stl_vector.h
b/libstdc++-v3/include/bits/stl_vector.h
index 0c9b74fdbb24..9ddf35502e69 100644
--- a/libstdc++-v3/include/bits/stl_vector.h
+++ b/libstdc++-v3/include/bits/stl_vector.h
@@ -2383,7 +2383,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
#if __glibcxx_containers_ranges // C++ >= 23
template<ranges::input_range _Rg,
- typename _Alloc = allocator<ranges::range_value_t<_Rg>>>
+ __allocator_like _Alloc = allocator<ranges::range_value_t<_Rg>>>
vector(from_range_t, _Rg&&, _Alloc = _Alloc())
-> vector<ranges::range_value_t<_Rg>, _Alloc>;
#endif
diff --git a/libstdc++-v3/include/debug/deque b/libstdc++-v3/include/debug/deque
index 9fba4ffc4997..00b4220051e7 100644
--- a/libstdc++-v3/include/debug/deque
+++ b/libstdc++-v3/include/debug/deque
@@ -715,7 +715,7 @@ namespace __debug
#if __glibcxx_containers_ranges // C++ >= 23
template<ranges::input_range _Rg,
- typename _Alloc = allocator<ranges::range_value_t<_Rg>>>
+ __allocator_like _Alloc = allocator<ranges::range_value_t<_Rg>>>
deque(from_range_t, _Rg&&, _Alloc = _Alloc())
-> deque<ranges::range_value_t<_Rg>, _Alloc>;
#endif
diff --git a/libstdc++-v3/include/debug/vector
b/libstdc++-v3/include/debug/vector
index 61e5ff78a7a4..56645d1e92c3 100644
--- a/libstdc++-v3/include/debug/vector
+++ b/libstdc++-v3/include/debug/vector
@@ -1001,7 +1001,7 @@ namespace __debug
#if __glibcxx_containers_ranges // C++ >= 23
template<ranges::input_range _Rg,
- typename _Alloc = allocator<ranges::range_value_t<_Rg>>>
+ __allocator_like _Alloc = allocator<ranges::range_value_t<_Rg>>>
vector(from_range_t, _Rg&&, _Alloc = _Alloc())
-> vector<ranges::range_value_t<_Rg>, _Alloc>;
#endif
diff --git a/libstdc++-v3/testsuite/23_containers/deque/cons/deduction_c++23.cc
b/libstdc++-v3/testsuite/23_containers/deque/cons/deduction_c++23.cc
new file mode 100644
index 000000000000..5893de92dc6f
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/deque/cons/deduction_c++23.cc
@@ -0,0 +1,14 @@
+// { dg-do compile { target c++23 } }
+
+#include <deque>
+#include <testsuite_iterators.h>
+
+using Range = __gnu_test::test_input_range<int>;
+
+template<typename Alloc>
+concept can_deduce_deque = requires(Range r, Alloc a) {
+ std::deque(std::from_range, r, a);
+};
+
+// Deduction should fail because int does not qualify as an allocator.
+static_assert( ! can_deduce_deque<int> );
diff --git
a/libstdc++-v3/testsuite/23_containers/vector/cons/deduction_c++23.cc
b/libstdc++-v3/testsuite/23_containers/vector/cons/deduction_c++23.cc
new file mode 100644
index 000000000000..1a442a8ed5c2
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/vector/cons/deduction_c++23.cc
@@ -0,0 +1,14 @@
+// { dg-do compile { target c++23 } }
+
+#include <vector>
+#include <testsuite_iterators.h>
+
+using Range = __gnu_test::test_input_range<int>;
+
+template<typename Alloc>
+concept can_deduce_vector = requires(Range r, Alloc a) {
+ std::vector(std::from_range, r, a);
+};
+
+// Deduction should fail because int does not qualify as an allocator.
+static_assert( ! can_deduce_vector<int> );
--
2.54.0
