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.

In order to give deprecated warnings even in C++98 mode this patch makes
_GLIBCXX_DEPRECATED work even for C++98, adds _GLIBCXX11_DEPRECATED for
the old meaning of _GLIBCXX_DEPRECATED, and adds new macros such as
_GLIBCXX_DEPRECATED_SUGGEST for suggesting alternatives to deprecated
features.

libstdc++-v3/ChangeLog:

	* include/bits/c++config (_GLIBCXX_DEPRECATED): Define for all
	standard modes.
	(_GLIBCXX_DEPRECATED_SUGGEST): New macro for "use 'foo' instead"
	message in deprecated warnings.
	(_GLIBCXX11_DEPRECATED, _GLIBCXX11_DEPRECATED_SUGGEST): New
	macros for marking features derpecated in C++11.
	(_GLIBCXX17_DEPRECATED_SUGGEST, _GLIBCXX20_DEPRECATED_SUGGEST):
	New macros.
	* include/backward/auto_ptr.h (auto_ptr_ref, auto_ptr<void>):
	Use _GLIBCXX11_DEPRECATED instead of _GLIBCXX_DEPRECATED.
	(auto_ptr): Use _GLIBCXX11_DEPRECATED_SUGGEST.
	* include/backward/binders.h (binder1st, binder2nd): Likewise.
	* 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.

7 files changed, 45 insertions, 18 deletions

diff --git a/libstdc++-v3/include/backward/auto_ptr.h b/libstdc++-v3/include/backward/auto_ptr.h
index 8511636..0863a08 100644
--- a/libstdc++-v3/include/backward/auto_ptr.h
+++ b/libstdc++-v3/include/backward/auto_ptr.h
@@ -51,7 +51,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       
       explicit
       auto_ptr_ref(_Tp1* __p): _M_ptr(__p) { }
-    } _GLIBCXX_DEPRECATED;
+    } _GLIBCXX11_DEPRECATED;
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
@@ -284,7 +284,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       template<typename _Tp1>
         operator auto_ptr<_Tp1>() throw()
         { return auto_ptr<_Tp1>(this->release()); }
-    } _GLIBCXX_DEPRECATED;
+    } _GLIBCXX11_DEPRECATED_SUGGEST("std::unique_ptr");
 
   // _GLIBCXX_RESOLVE_LIB_DEFECTS
   // 541. shared_ptr template assignment and void
@@ -293,7 +293,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
     public:
       typedef void element_type;
-    } _GLIBCXX_DEPRECATED;
+    } _GLIBCXX11_DEPRECATED;
 
 #if __cplusplus >= 201103L
   template<_Lock_policy _Lp>
diff --git a/libstdc++-v3/include/backward/binders.h b/libstdc++-v3/include/backward/binders.h
index 8c2c00d..e3029e7 100644
--- a/libstdc++-v3/include/backward/binders.h
+++ b/libstdc++-v3/include/backward/binders.h
@@ -127,7 +127,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typename _Operation::result_type
       operator()(typename _Operation::second_argument_type& __x) const
       { return op(value, __x); }
-    } _GLIBCXX_DEPRECATED;
+    } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");
 
   /// One of the @link binders binder functors@endlink.
   template<typename _Operation, typename _Tp>
@@ -162,7 +162,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typename _Operation::result_type
       operator()(typename _Operation::first_argument_type& __x) const
       { return op(__x, value); }
-    } _GLIBCXX_DEPRECATED;
+    } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");
 
   /// One of the @link binders binder functors@endlink.
   template<typename _Operation, typename _Tp>
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index b1fad59..116faf6 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -83,22 +83,37 @@
 # define _GLIBCXX_USE_DEPRECATED 1
 #endif
 
-#if defined(__DEPRECATED) && (__cplusplus >= 201103L)
+#if defined(__DEPRECATED)
 # 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 >= 201103L)
+# define _GLIBCXX11_DEPRECATED _GLIBCXX_DEPRECATED
+# define _GLIBCXX11_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
+#else
+# define _GLIBCXX11_DEPRECATED
+# define _GLIBCXX11_DEPRECATED_SUGGEST(ALT)
 #endif
 
 #if defined(__DEPRECATED) && (__cplusplus >= 201703L)
 # define _GLIBCXX17_DEPRECATED [[__deprecated__]]
+# define _GLIBCXX17_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
 #else
 # define _GLIBCXX17_DEPRECATED
+# define _GLIBCXX17_DEPRECATED_SUGGEST(ALT)
 #endif
 
 #if defined(__DEPRECATED) && (__cplusplus > 201703L)
 # define _GLIBCXX20_DEPRECATED(MSG) [[deprecated(MSG)]]
+# define _GLIBCXX20_DEPRECATED_SUGGEST(ALT) _GLIBCXX_DEPRECATED_SUGGEST(ALT)
 #else
 # define _GLIBCXX20_DEPRECATED(MSG)
+# define _GLIBCXX20_DEPRECATED_SUGGEST(ALT)
 #endif
 
 // Macros for ABI tag attributes.
diff --git a/libstdc++-v3/include/bits/ios_base.h b/libstdc++-v3/include/bits/ios_base.h
index d656254..4ac0265 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 3e51236..cae35e7 100644
--- a/libstdc++-v3/include/std/streambuf
+++ b/libstdc++-v3/include/std/streambuf
@@ -784,9 +784,7 @@ _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 62f1190..6ced781 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 40255ec..a565c20 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" }
 }