[gcc r13-2311] libstdc++: Improve comments in std::reference_wrapper tests

[Jonathan Wakely]

https://gcc.gnu.org/g:5d27fcd993e4519fc05224f48bd2492b6cf52be1

commit r13-2311-g5d27fcd993e4519fc05224f48bd2492b6cf52be1
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Aug 31 13:44:45 2022 +0100

    libstdc++: Improve comments in std::reference_wrapper tests
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/20_util/reference_wrapper/invoke-2.cc: Improve
            comments.
            * testsuite/20_util/reference_wrapper/invoke-3.cc: Likewise.
            * testsuite/20_util/reference_wrapper/invoke.cc: Likewise.

Diff:
---
 libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-2.cc | 3 ++-
 libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-3.cc | 3 ++-
 libstdc++-v3/testsuite/20_util/reference_wrapper/invoke.cc   | 2 ++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-2.cc b/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-2.cc
index 2741510e756..fd3430cf0a9 100644
--- a/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-2.cc
+++ b/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-2.cc
@@ -16,7 +16,7 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
-// 20.6.4 function object return types [func.ret]
+// C++11 20.8.3.4 reference_wrapper invocation [refwrap.invoke]
 #include <functional>
 
 struct X
@@ -27,6 +27,7 @@ struct X
 
 void test01()
 {
+  // PR libstdc++/48521 std::result_of doesn't work with pointer to member
   typedef int (X::*mfp)(int);
   typedef int X::*mp;
   mfp m = &X::f;
diff --git a/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-3.cc b/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-3.cc
index e4124c9b57c..c25315b6751 100644
--- a/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-3.cc
+++ b/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke-3.cc
@@ -17,7 +17,7 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
-// 20.8.3.4 reference_wrapper invocation [refwrap.invoke]
+// C++11 20.8.3.4 reference_wrapper invocation [refwrap.invoke]
 #include <functional>
 
 struct ABC
@@ -33,4 +33,5 @@ struct Concrete : ABC
 Concrete c;
 ABC& abc = c;
 
+// PR libstdc++/57336 Cannot INVOKE a reference_wrapper around an abstract type
 auto b = std::cref(abc)();
diff --git a/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke.cc b/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke.cc
index cd884fe66eb..b2abc812b79 100644
--- a/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke.cc
+++ b/libstdc++-v3/testsuite/20_util/reference_wrapper/invoke.cc
@@ -17,6 +17,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// C++11 20.8.3.4 reference_wrapper invocation [refwrap.invoke]
+
 #include <functional>
 #include <type_traits>
 #include <testsuite_hooks.h>