Re: [ PATCH ] [ C++ ] Implementing P0767 - deprecate POD

[Jonathan Wakely <jwakely at redhat dot com>]

On 09/01/20 19:57 +0000, Jonathan Wakely wrote:
> I'll commit the attached patch after more testing.

And this follow-up to fix some fallout.


commit 212e166cbeb4c7df38436563c3c51dbd4e0efc0d
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Jan 9 19:55:17 2020 +0000

    libstdc++: Fix testsuite failures and warnings due to is_pod deprecation
    
    With -std=gnu++2a and -Wsystem-headers the std::is_pod deprecation
    causes some new diagnostics. This suppresses them.
    
            * include/experimental/type_traits (experimental::is_pod_v): Disable
            -Wdeprecated-declarations warnings around reference to std::is_pod.
            * include/std/type_traits (is_pod_v): Likewise.
            * testsuite/18_support/max_align_t/requirements/2.cc: Also check
            is_standard_layout and is_trivial. Do not check is_pod for C++20.
            * testsuite/20_util/is_pod/requirements/explicit_instantiation.cc:
            Add -Wno-deprecated for C++20.
            * testsuite/20_util/is_pod/requirements/typedefs.cc: Likewise.
            * testsuite/20_util/is_pod/value.cc: Likewise.
            * testsuite/experimental/type_traits/value.cc: Likewise.

diff --git a/libstdc++-v3/include/experimental/type_traits b/libstdc++-v3/include/experimental/type_traits
index a84ddd45ff1..a92c385c029 100644
--- a/libstdc++-v3/include/experimental/type_traits
+++ b/libstdc++-v3/include/experimental/type_traits
@@ -110,8 +110,11 @@ template <typename _Tp>
   constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
 template <typename _Tp>
   constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 template <typename _Tp>
   constexpr bool is_pod_v = is_pod<_Tp>::value;
+#pragma GCC diagnostic pop
 template <typename _Tp>
   constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
 template <typename _Tp>
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index c69867c2ae0..6aa2cedfa0a 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -3079,9 +3079,12 @@ template <typename _Tp>
     is_trivially_copyable<_Tp>::value;
 template <typename _Tp>
   inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 template <typename _Tp>
   _GLIBCXX20_DEPRECATED("use is_standard_layout_v && is_trivial_v instead")
   inline constexpr bool is_pod_v = is_pod<_Tp>::value;
+#pragma GCC diagnostic pop
 template <typename _Tp>
   inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
 template <typename _Tp>
diff --git a/libstdc++-v3/testsuite/18_support/max_align_t/requirements/2.cc b/libstdc++-v3/testsuite/18_support/max_align_t/requirements/2.cc
index 97036ed3134..7e496967156 100644
--- a/libstdc++-v3/testsuite/18_support/max_align_t/requirements/2.cc
+++ b/libstdc++-v3/testsuite/18_support/max_align_t/requirements/2.cc
@@ -20,4 +20,8 @@
 #include <cstddef>
 #include <type_traits>
 
+#if __cplusplus <= 201703L
 static_assert (std::is_pod<std::max_align_t>::value, "");
+#endif
+static_assert (std::is_standard_layout<std::max_align_t>::value, "");
+static_assert (std::is_trivial<std::max_align_t>::value, "");
diff --git a/libstdc++-v3/testsuite/20_util/is_pod/requirements/explicit_instantiation.cc b/libstdc++-v3/testsuite/20_util/is_pod/requirements/explicit_instantiation.cc
index 7ee41b33d7c..b41a59338bb 100644
--- a/libstdc++-v3/testsuite/20_util/is_pod/requirements/explicit_instantiation.cc
+++ b/libstdc++-v3/testsuite/20_util/is_pod/requirements/explicit_instantiation.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-deprecated" { target { c++2a } } }
 // 2010-02-21  Paolo Carlini  <paolo.carlini@oracle.com>
 
 // Copyright (C) 2010-2020 Free Software Foundation, Inc.
diff --git a/libstdc++-v3/testsuite/20_util/is_pod/requirements/typedefs.cc b/libstdc++-v3/testsuite/20_util/is_pod/requirements/typedefs.cc
index 492f0ea956f..888895719b7 100644
--- a/libstdc++-v3/testsuite/20_util/is_pod/requirements/typedefs.cc
+++ b/libstdc++-v3/testsuite/20_util/is_pod/requirements/typedefs.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-deprecated" { target { c++2a } } }
 
 // 2010-02-21  Paolo Carlini  <paolo.carlini@oracle.com>
 //
diff --git a/libstdc++-v3/testsuite/20_util/is_pod/value.cc b/libstdc++-v3/testsuite/20_util/is_pod/value.cc
index 5a856309ad5..659d9d4d8ae 100644
--- a/libstdc++-v3/testsuite/20_util/is_pod/value.cc
+++ b/libstdc++-v3/testsuite/20_util/is_pod/value.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-deprecated" { target { c++2a } } }
 
 // 2010-02-21  Paolo Carlini  <pcarlini@suse.de>
 //
diff --git a/libstdc++-v3/testsuite/experimental/type_traits/value.cc b/libstdc++-v3/testsuite/experimental/type_traits/value.cc
index 156753b4b5e..0e1176dd14a 100644
--- a/libstdc++-v3/testsuite/experimental/type_traits/value.cc
+++ b/libstdc++-v3/testsuite/experimental/type_traits/value.cc
@@ -1,4 +1,5 @@
 // { dg-do compile { target c++14 } }
+// { dg-additional-options "-Wno-deprecated" { target { c++2a } } }
 
 // Copyright (C) 2014-2020 Free Software Foundation, Inc.
 //