On 2/11/26 7:01 AM, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk?
OK.
-- >8 --
As explained in one of Tomasz's library papers P2438R2[1], C++20 allows
member functions to have both ref-qualified and non-ref-qualified
overloads, but at the time of writing no compiler supported that. This
patch implements this C++20 relaxation so that we can in turn implement
P2438R2 as originally intended -- without needing to change the
signature of the original string::substr overload.
[1]: https://wg21.link/P2438R2#_modifying_existing_const_overload
PR c++/98939
PR libstdc++/119745
gcc/cp/ChangeLog:
* class.cc (object_parms_correspond): Allow differing
FUNCTION_REF_QUALIFIED in C++20.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/ref-qual5.C: Expect no diagnostics in C++20.
---
gcc/cp/class.cc | 7 ++++---
gcc/testsuite/g++.dg/cpp0x/ref-qual5.C | 7 ++++---
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc
index 315ffd316ffb..a223f71dbbe9 100644
--- a/gcc/cp/class.cc
+++ b/gcc/cp/class.cc
@@ -1223,9 +1223,10 @@ object_parms_correspond (tree fn, tree method, tree
context)
&& DECL_IOBJ_MEMBER_FUNCTION_P (method))
{
/* Either both or neither need to be ref-qualified for
- differing quals to allow overloading. */
- if ((FUNCTION_REF_QUALIFIED (fn_type)
- == FUNCTION_REF_QUALIFIED (method_type))
+ differing quals to allow overloading before C++20 (P1787R6). */
+ if ((cxx_dialect >= cxx20
+ || (FUNCTION_REF_QUALIFIED (fn_type)
+ == FUNCTION_REF_QUALIFIED (method_type)))
&& (type_memfn_quals (fn_type) != type_memfn_quals (method_type)
|| type_memfn_rqual (fn_type) != type_memfn_rqual (method_type)))
return false;
diff --git a/gcc/testsuite/g++.dg/cpp0x/ref-qual5.C
b/gcc/testsuite/g++.dg/cpp0x/ref-qual5.C
index e3d26e5a78fa..42e9bd3b4aee 100644
--- a/gcc/testsuite/g++.dg/cpp0x/ref-qual5.C
+++ b/gcc/testsuite/g++.dg/cpp0x/ref-qual5.C
@@ -1,5 +1,6 @@
// 13.1: ...cannot be overloaded if any of them, but not all, have a
// ref-qualifier.
+// In C++20 this was relaxed by P1787R6 "Declarations and where to find them"
// { dg-require-effective-target c++11 }
@@ -7,7 +8,7 @@ class Y {
void h() &;
void h() const &; // OK
void h() &&; // OK, all declarations have a
ref-qualifier
- void i() &; // { dg-message "" }
- void i() const; // { dg-error "" } prior declaration of i
- // has a ref-qualifier
+ void i() &; // { dg-message "" "" { target c++17_down } }
+ void i() const; // { dg-error "" "" { target c++17_down } }
+ // prior declaration of i has a ref-qualifier
};
