[gcc r12-9348] libstdc++: Make operator<< for stacktraces less templated (LWG 3515)

[Jonathan Wakely]

https://gcc.gnu.org/g:f6c6df050a3e04744f81a471a53864ee2291ef4a

commit r12-9348-gf6c6df050a3e04744f81a471a53864ee2291ef4a
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Dec 9 14:59:01 2022 +0000

    libstdc++: Make operator<< for stacktraces less templated (LWG 3515)
    
    This change was approved for C++23 last month.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/stacktrace (operator<<): Only output to narrow
            ostreams (LWG 3515).
            * testsuite/19_diagnostics/stacktrace/synopsis.cc:
    
    (cherry picked from commit 2327d9331430777006008ab3b051afe2b4fc15bd)

Diff:
---
 libstdc++-v3/include/std/stacktrace                | 38 ++++++++++------------
 .../19_diagnostics/stacktrace/synopsis.cc          | 11 +++----
 2 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/libstdc++-v3/include/std/stacktrace b/libstdc++-v3/include/std/stacktrace
index a067d629a16..a7fee8531f7 100644
--- a/libstdc++-v3/include/std/stacktrace
+++ b/libstdc++-v3/include/std/stacktrace
@@ -160,9 +160,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       return __state;
     }
 
-    template<typename _CharT, typename _Traits>
-      friend basic_ostream<_CharT, _Traits>&
-      operator<<(basic_ostream<_CharT, _Traits>&, const stacktrace_entry&);
+    friend ostream&
+    operator<<(ostream&, const stacktrace_entry&);
 
     bool
     _M_get_info(string* __desc, string* __file, int* __line) const
@@ -713,25 +712,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     noexcept(noexcept(__a.swap(__b)))
     { __a.swap(__b); }
 
-  template<typename _CharT, typename _Traits>
-    inline basic_ostream<_CharT, _Traits>&
-    operator<<(basic_ostream<_CharT, _Traits>& __os,
-	       const stacktrace_entry& __f)
-    {
-      string __desc, __file;
-      int __line;
-      if (__f._M_get_info(&__desc, &__file, &__line))
-	{
-	  __os.width(4);
-	  __os << __desc << " at " << __file << ':' << __line;
-	}
-      return __os;
-    }
+  inline ostream&
+  operator<<(ostream& __os, const stacktrace_entry& __f)
+  {
+    string __desc, __file;
+    int __line;
+    if (__f._M_get_info(&__desc, &__file, &__line))
+      {
+	__os.width(4);
+	__os << __desc << " at " << __file << ':' << __line;
+      }
+    return __os;
+  }
 
-  template<typename _CharT, typename _Traits, typename _Allocator>
-    inline basic_ostream<_CharT, _Traits>&
-    operator<<(basic_ostream<_CharT, _Traits>& __os,
-	       const basic_stacktrace<_Allocator>& __st)
+  template<typename _Allocator>
+    inline ostream&
+    operator<<(ostream& __os, const basic_stacktrace<_Allocator>& __st)
     {
       for (stacktrace::size_type __i = 0; __i < __st.size(); ++__i)
 	{
diff --git a/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc b/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc
index 72582fa53c6..262abea21ec 100644
--- a/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc
+++ b/libstdc++-v3/testsuite/19_diagnostics/stacktrace/synopsis.cc
@@ -28,13 +28,12 @@ namespace std
   template<class Allocator>
     string to_string(const basic_stacktrace<Allocator>& st);
 
-  template<class charT, class traits>
-    basic_ostream<charT, traits>&
-    operator<<(basic_ostream<charT, traits>& os, const stacktrace_entry& f);
+  ostream&
+  operator<<(ostream& os, const stacktrace_entry& f);
 
-  template<class charT, class traits, class Allocator>
-    basic_ostream<charT, traits>&
-    operator<<(basic_ostream<charT, traits>& os, const basic_stacktrace<Allocator>& st);
+  template<class Allocator>
+    ostream&
+    operator<<(ostream& os, const basic_stacktrace<Allocator>& st);
 
   namespace pmr {
     using stacktrace = basic_stacktrace<polymorphic_allocator<stacktrace_entry>>;