Tested on x86_64-pc-linux-gnu, does this look OK for trunk/16?
-- >8 --
This implements the [util.smartptr.shared.const] constraints on the
constructors that take a deleter (which before C++20 were requirements
rather than constraints).
PR libstdc++/126120
libstdc++-v3/ChangeLog:
* include/bits/shared_ptr.h
(shared_ptr::shared_ptr(nullptr_t, ...)): Add _Constructible
constraint to verify __shared_ptr base initialization is
well-formed.
* include/bits/shared_ptr_base.h (_ValidDeleter): New __enable_if_t
constraint.
(__shared_ptr::__shared_ptr(..., _Deleter, ...)): Remove
static_assert checking deleter invocability. Add _ValidDeleter
constraint.
* testsuite/20_util/shared_ptr/cons/126120.cc: New test.
---
libstdc++-v3/include/bits/shared_ptr.h | 5 +--
libstdc++-v3/include/bits/shared_ptr_base.h | 29 ++++++++---------
.../20_util/shared_ptr/cons/126120.cc | 31 +++++++++++++++++++
3 files changed, 49 insertions(+), 16 deletions(-)
create mode 100644 libstdc++-v3/testsuite/20_util/shared_ptr/cons/126120.cc
diff --git a/libstdc++-v3/include/bits/shared_ptr.h
b/libstdc++-v3/include/bits/shared_ptr.h
index 8be9aace1711..28b8a3ca8f29 100644
--- a/libstdc++-v3/include/bits/shared_ptr.h
+++ b/libstdc++-v3/include/bits/shared_ptr.h
@@ -225,7 +225,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*
* The last owner will call __d(__p)
*/
- template<typename _Deleter>
+ template<typename _Deleter, typename = _Constructible<nullptr_t,
_Deleter>>
shared_ptr(nullptr_t __p, _Deleter __d)
: __shared_ptr<_Tp>(__p, std::move(__d)) { }
@@ -264,7 +264,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*
* The last owner will call __d(__p)
*/
- template<typename _Deleter, typename _Alloc>
+ template<typename _Deleter, typename _Alloc,
+ typename = _Constructible<nullptr_t, _Deleter, _Alloc>>
shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
: __shared_ptr<_Tp>(__p, std::move(__d), std::move(__a)) { }
diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h
b/libstdc++-v3/include/bits/shared_ptr_base.h
index c8342b7904a5..2eb3436183ee 100644
--- a/libstdc++-v3/include/bits/shared_ptr_base.h
+++ b/libstdc++-v3/include/bits/shared_ptr_base.h
@@ -1469,6 +1469,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return static_cast<const __shared_ptr<_Tp, _Lp>*>(this)->get(); }
};
+ // Constraint for well-formedness of deleter expression d(p):
+ template<typename _Deleter, typename _Up>
+ using _ValidDeleter = __enable_if_t<__and_<
+ is_move_constructible<_Deleter>,
+ __is_invocable<_Deleter&, _Up&>
+ >::value>;
+
template<typename _Tp, _Lock_policy _Lp>
class __shared_ptr
: public __shared_ptr_access<_Tp, _Lp>
@@ -1524,31 +1531,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_enable_shared_from_this_with(__p);
}
- template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>>
+ template<typename _Yp, typename _Deleter, typename = _SafeConv<_Yp>,
+ typename = _ValidDeleter<_Deleter, _Yp*>>
__shared_ptr(_Yp* __p, _Deleter __d)
: _M_ptr(__p), _M_refcount(__p, std::move(__d))
- {
- static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
- "deleter expression d(p) is well-formed");
- _M_enable_shared_from_this_with(__p);
- }
+ { _M_enable_shared_from_this_with(__p); }
template<typename _Yp, typename _Deleter, typename _Alloc,
- typename = _SafeConv<_Yp>>
+ typename = _SafeConv<_Yp>, typename = _ValidDeleter<_Deleter,
_Yp*>>
__shared_ptr(_Yp* __p, _Deleter __d, _Alloc __a)
: _M_ptr(__p), _M_refcount(__p, std::move(__d), std::move(__a))
- {
- static_assert(__is_invocable<_Deleter&, _Yp*&>::value,
- "deleter expression d(p) is well-formed");
- _M_enable_shared_from_this_with(__p);
- }
+ { _M_enable_shared_from_this_with(__p); }
- template<typename _Deleter>
+ template<typename _Deleter, typename = _ValidDeleter<_Deleter,
nullptr_t>>
__shared_ptr(nullptr_t __p, _Deleter __d)
: _M_ptr(0), _M_refcount(__p, std::move(__d))
{ }
- template<typename _Deleter, typename _Alloc>
+ template<typename _Deleter, typename _Alloc,
+ typename = _ValidDeleter<_Deleter, nullptr_t>>
__shared_ptr(nullptr_t __p, _Deleter __d, _Alloc __a)
: _M_ptr(0), _M_refcount(__p, std::move(__d), std::move(__a))
{ }
diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/cons/126120.cc
b/libstdc++-v3/testsuite/20_util/shared_ptr/cons/126120.cc
new file mode 100644
index 000000000000..a5a29597e078
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/shared_ptr/cons/126120.cc
@@ -0,0 +1,31 @@
+// PR libstdc++/126120 - is_constructible_v with shared_ptr from an invalid
deleter
+// { dg-do compile { target c++11 } }
+
+#include <memory>
+#include <type_traits>
+
+struct NonDeleter { };
+
+struct NonMoveableDeleter {
+ NonMoveableDeleter() = default;
+ NonMoveableDeleter(const NonMoveableDeleter&) = delete;
+ void operator()(int* p) const { delete p; }
+};
+
+using Alloc = std::allocator<int>;
+
+// 1. Pointer + Deleter
+static_assert( ! std::is_constructible<std::shared_ptr<int>, int*,
NonDeleter>::value, "");
+static_assert( ! std::is_constructible<std::shared_ptr<int>, int*,
NonMoveableDeleter>::value, "");
+
+// 2. Pointer + Deleter + Allocator
+static_assert( ! std::is_constructible<std::shared_ptr<int>, int*, NonDeleter,
Alloc>::value, "");
+static_assert( ! std::is_constructible<std::shared_ptr<int>, int*,
NonMoveableDeleter, Alloc>::value, "");
+
+// 3. nullptr_t + Deleter
+static_assert( ! std::is_constructible<std::shared_ptr<int>, std::nullptr_t,
NonDeleter>::value, "");
+static_assert( ! std::is_constructible<std::shared_ptr<int>, std::nullptr_t,
NonMoveableDeleter>::value, "");
+
+// 4. nullptr_t + Deleter + Allocator
+static_assert( ! std::is_constructible<std::shared_ptr<int>, std::nullptr_t,
NonDeleter, Alloc>::value, "");
+static_assert( ! std::is_constructible<std::shared_ptr<int>, std::nullptr_t,
NonMoveableDeleter, Alloc>::value, "");
--
2.55.0.669.g593c42fe07
