[gcc r10-8644] libstdc++: Add deprecated attributes to old iostream members

[gcc r10-8644] libstdc++: Add deprecated attributes to old iostream members

[Jonathan Wakely]

https://gcc.gnu.org/g:817ac30a8581f75cc25c4c71ef8623eb52953390

commit r10-8644-g817ac30a8581f75cc25c4c71ef8623eb52953390
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Aug 19 13:41:26 2020 +0100

    libstdc++: Add deprecated attributes to old iostream members
    
    Back in 2017 I removed these prehistoric members (which were deprecated
    since C++98) for C++17 mode. But I didn't add deprecated attributes to
    most of them, so users didn't get any warning they would be going away.
    Apparently some poor souls do actually use some of these names, and so
    now that GCC 11 defaults to -std=gnu++17 some code has stopped
    compiling.
    
    This adds deprecated attributes to them, so that C++98/03/11/14 code
    will get a warning if it uses them. I'll also backport this to the
    release branches so that users can find out about the deprecation before
    they start using C++17.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/c++config (_GLIBCXX_DEPRECATED_SUGGEST): New
            macro for "use 'foo' instead" message in deprecated warnings.
            * include/bits/ios_base.h (io_state, open_mode, seek_dir)
            (streampos, streamoff): Use _GLIBCXX_DEPRECATED_SUGGEST.
            * include/std/streambuf (stossc): Replace C++11 attribute
            with _GLIBCXX_DEPRECATED_SUGGEST.
            * include/std/type_traits (__is_nullptr_t): Use
            _GLIBCXX_DEPRECATED_SUGGEST instead of _GLIBCXX_DEPRECATED.
            * testsuite/27_io/types/1.cc: Check for deprecated warnings.
            Also check for io_state, open_mode and seek_dir typedefs.
    
    (cherry picked from commit eef9bf4ca8d90a1751bc4bff03722ee68999eb8e)

Diff:
---
 libstdc++-v3/include/bits/c++config     |  4 ++++
 libstdc++-v3/include/bits/ios_base.h    | 17 +++++++++++------
 libstdc++-v3/include/std/streambuf      |  4 +---
 libstdc++-v3/include/std/type_traits    |  2 +-
 libstdc++-v3/testsuite/27_io/types/1.cc | 13 +++++++++++--
 5 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index b1fad59d4b3..aa94a681fff 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -77,6 +77,7 @@
 // Macros for deprecated attributes.
 //   _GLIBCXX_USE_DEPRECATED
 //   _GLIBCXX_DEPRECATED
+//   _GLIBCXX_DEPRECATED_SUGGEST
 //   _GLIBCXX17_DEPRECATED
 //   _GLIBCXX20_DEPRECATED( string-literal )
 #ifndef _GLIBCXX_USE_DEPRECATED
@@ -85,8 +86,11 @@
 
 #if defined(__DEPRECATED) && (__cplusplus >= 201103L)
 # define _GLIBCXX_DEPRECATED __attribute__ ((__deprecated__))
+# define _GLIBCXX_DEPRECATED_SUGGEST(ALT) \
+  __attribute__ ((__deprecated__ ("use '" ALT "' instead")))
 #else
 # define _GLIBCXX_DEPRECATED
+# define _GLIBCXX_DEPRECATED_SUGGEST(ALT)
 #endif
 
 #if defined(__DEPRECATED) && (__cplusplus >= 201703L)
diff --git a/libstdc++-v3/include/bits/ios_base.h b/libstdc++-v3/include/bits/ios_base.h
index d6562544f4d..4ac026547b4 100644
--- a/libstdc++-v3/include/bits/ios_base.h
+++ b/libstdc++-v3/include/bits/ios_base.h
@@ -471,12 +471,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 #if __cplusplus <= 201402L
     // Annex D.6 (removed in C++17)
-    typedef int io_state;
-    typedef int open_mode;
-    typedef int seek_dir;
-
-    typedef std::streampos streampos;
-    typedef std::streamoff streamoff;
+    typedef int io_state
+      _GLIBCXX_DEPRECATED_SUGGEST("std::iostate");
+    typedef int open_mode
+      _GLIBCXX_DEPRECATED_SUGGEST("std::openmode");
+    typedef int seek_dir
+      _GLIBCXX_DEPRECATED_SUGGEST("std::seekdir");
+
+    typedef std::streampos streampos
+      _GLIBCXX_DEPRECATED_SUGGEST("std::streampos");
+    typedef std::streamoff streamoff
+      _GLIBCXX_DEPRECATED_SUGGEST("std::streamoff");
 #endif
 
     // Callbacks;
diff --git a/libstdc++-v3/include/std/streambuf b/libstdc++-v3/include/std/streambuf
index f8e4cb9879c..7cb4fabbb89 100644
--- a/libstdc++-v3/include/std/streambuf
+++ b/libstdc++-v3/include/std/streambuf
@@ -786,9 +786,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *
        *  See http://gcc.gnu.org/ml/libstdc++/2002-05/msg00168.html
        */
-#if __cplusplus >= 201103L
-      [[__deprecated__("stossc is deprecated, use sbumpc instead")]]
-#endif
+      _GLIBCXX_DEPRECATED_SUGGEST("std::basic_streambuf::sbumpc")
       void
       stossc()
       {
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index bc9a45b3746..c62dc72d3d7 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -518,7 +518,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp>
     struct __is_nullptr_t
     : public is_null_pointer<_Tp>
-    { } _GLIBCXX_DEPRECATED;
+    { } _GLIBCXX_DEPRECATED_SUGGEST("std::is_null_pointer");
 
   // Composite type categories.
 
diff --git a/libstdc++-v3/testsuite/27_io/types/1.cc b/libstdc++-v3/testsuite/27_io/types/1.cc
index 40255ec51d1..a565c205b35 100644
--- a/libstdc++-v3/testsuite/27_io/types/1.cc
+++ b/libstdc++-v3/testsuite/27_io/types/1.cc
@@ -15,6 +15,7 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+// { dg-options "-Wdeprecated" }
 // { dg-do compile { target c++14_down } }
 
 // 27.4.2.1 - Types [lib.ios.types]
@@ -26,6 +27,14 @@
 // Annex D, deprecated.
 void test01()
 {
-  typedef std::ios_base::streampos streampos_type;
-  typedef std::ios_base::streamoff streamoff_type;
+  typedef std::ios_base::streampos streampos_type; // { dg-warning "is deprecated: use 'std::streampos' instead" }
+  typedef std::ios_base::streamoff streamoff_type; // { dg-warning "is deprecated: use 'std::streamoff' instead" }
+}
+
+// Annex D, deprecated.
+void test02()
+{
+  typedef std::ios_base::io_state iostate_type; // { dg-warning "is deprecated: use 'std::iostate' instead" }
+  typedef std::ios_base::open_mode openmode_type; // { dg-warning "is deprecated: use 'std::openmode' instead" }
+  typedef std::ios_base::seek_dir seekdir_type; // { dg-warning "is deprecated: use 'std::seekdir' instead" }
 }