Teted x86_64-linux. Pushed to trunk.
-- >8 --
This makes the deduction guides for std::function and std::packaged_task
work for explicit object member functions, i.e. "deducing this", as per
LWG 3617.
libstdc++-v3/ChangeLog:
PR libstdc++/113335
* include/bits/std_function.h (__function_guide_helper): Add
partial specialization for explicit object member functions, as
per LWG 3617.
* testsuite/20_util/function/cons/deduction_c++23.cc: Check
explicit object member functions.
* testsuite/30_threads/packaged_task/cons/deduction_c++23.cc:
Likewise.
---
libstdc++-v3/include/bits/std_function.h | 6 ++++
.../20_util/function/cons/deduction_c++23.cc | 35 +++++++++++++++++++
.../packaged_task/cons/deduction_c++23.cc | 35 +++++++++++++++++++
3 files changed, 76 insertions(+)
diff --git a/libstdc++-v3/include/bits/std_function.h
b/libstdc++-v3/include/bits/std_function.h
index 9130f9d28e3..79b59466fe9 100644
--- a/libstdc++-v3/include/bits/std_function.h
+++ b/libstdc++-v3/include/bits/std_function.h
@@ -697,6 +697,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
{ using type = _Res(_Args...); };
+#if __cpp_explicit_this_parameter >= 202110L
+ template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
+ struct __function_guide_helper<_Res (*) (_Tp, _Args...) noexcept(_Nx)>
+ { using type = _Res(_Args...); };
+#endif
+
#if __cpp_static_call_operator >= 202207L && __cpp_concepts >= 202002L
template<typename _StaticCallOp>
struct __function_guide_static_helper
diff --git a/libstdc++-v3/testsuite/20_util/function/cons/deduction_c++23.cc
b/libstdc++-v3/testsuite/20_util/function/cons/deduction_c++23.cc
index 132bfb8fbfe..8c70c102929 100644
--- a/libstdc++-v3/testsuite/20_util/function/cons/deduction_c++23.cc
+++ b/libstdc++-v3/testsuite/20_util/function/cons/deduction_c++23.cc
@@ -21,3 +21,38 @@ test_static_call_operator()
std::function func2 = F2{};
check_type<std::function<float(char, void*)>>(func2);
}
+
+void
+test_explicit_object_call_operator()
+{
+ // LWG 3617 - function/packaged_task deduction guides and deducing this
+ struct F {
+ int operator()(this const F&) { return 42; }
+ };
+
+ std::function g = F{};
+ check_type<std::function<int()>>(g);
+
+ struct F2 {
+ short operator()(this F2&, float&) { return 0; }
+ };
+
+ std::function g2 = F2{};
+ check_type<std::function<short(float&)>>(g2);
+
+ struct F3 {
+ void operator()(this const F3, char*, long) { }
+ };
+
+ std::function g3 = F3{};
+ check_type<std::function<void(char*, long)>>(g3);
+
+ struct F4 {
+ int i;
+ operator const int&() const { return i; }
+ const long& operator()(this int, const long& l) { return l; }
+ };
+
+ std::function g4 = F4{};
+ check_type<std::function<const long&(const long&)>>(g4);
+}
diff --git
a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/deduction_c++23.cc
b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/deduction_c++23.cc
index 6a43cf945d8..307522a73f5 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/deduction_c++23.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/deduction_c++23.cc
@@ -20,3 +20,38 @@ test_static_call_operator()
std::packaged_task task2{ F2{} };
check_type<std::packaged_task<float(char, void*)>>(task2);
}
+
+void
+test_explicit_object_call_operator()
+{
+ // LWG 3617 - function/packaged_task deduction guides and deducing this
+ struct F {
+ int operator()(this const F&) { return 42; }
+ };
+
+ std::packaged_task g{ F{} };
+ check_type<std::packaged_task<int()>>(g);
+
+ struct F2 {
+ short operator()(this F2&, float&) { return 0; }
+ };
+
+ std::packaged_task g2{ F2{} };
+ check_type<std::packaged_task<short(float&)>>(g2);
+
+ struct F3 {
+ void operator()(this const F3, char*, long) { }
+ };
+
+ std::packaged_task g3{ F3{} };
+ check_type<std::packaged_task<void(char*, long)>>(g3);
+
+ struct F4 {
+ int i;
+ operator const int&() const { return i; }
+ const long& operator()(this int, const long& l) { return l; }
+ };
+
+ std::packaged_task g4{ F4{} };
+ check_type<std::packaged_task<const long&(const long&)>>(g4);
+}
--
2.43.0
