[gcc(refs/vendors/ibm/heads/gcc-9-branch)] libstdc++: Mark experimental::net::system_context ctor deleted

[Peter Bergner <bergner@gcc.gnu.org>]

https://gcc.gnu.org/g:bdeb48c6d84c7651f180887c66f617aaaf598ac3

commit bdeb48c6d84c7651f180887c66f617aaaf598ac3
Author: Thomas Rodgers <rodgert@appliantology.com>
Date:   Thu Apr 23 13:42:46 2020 -0700

    libstdc++: Mark experimental::net::system_context ctor deleted
    
               Backport from mainline.
    
               * include/experimental/net/executor (system_context): Mark
               system_context::system_context() = delete.
               * testsuite/experimental/net/executor/1.cc: Add new
               test to check system_context is not default constructible.

Diff:
---
 libstdc++-v3/ChangeLog                             |   9 ++
 libstdc++-v3/include/experimental/executor         |   2 +-
 .../testsuite/experimental/net/executor/1.cc       | 100 +++++++++++++++++++++
 3 files changed, 110 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 3f9eb05afc0..9434ab185fe 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,12 @@
+2020-04-23  Thomas Rodgers  <rodgert@appliantology.com>
+
+	Backport from mainline
+	2020-04-23  Thomas Rodgers  <rodgert@appliantology.com>
+	* include/experimental/net/executor (system_context): Mark
+	system_context::system_context() = delete.
+	* testsuite/experimental/net/executor/1.cc: Add new
+	test to check system_context is not default constructible.
+
 2020-04-23  Thomas Rodgers  <trodgers@redhat.com>
 
 	Backport from mainline
diff --git a/libstdc++-v3/include/experimental/executor b/libstdc++-v3/include/experimental/executor
index 15f28de9b9d..9c0c7186234 100644
--- a/libstdc++-v3/include/experimental/executor
+++ b/libstdc++-v3/include/experimental/executor
@@ -854,7 +854,7 @@ inline namespace v1
 
     // construct / copy / destroy:
 
-    system_context() = default;
+    system_context() = delete;
     system_context(const system_context&) = delete;
     system_context& operator=(const system_context&) = delete;
 
diff --git a/libstdc++-v3/testsuite/experimental/net/executor/1.cc b/libstdc++-v3/testsuite/experimental/net/executor/1.cc
new file mode 100644
index 00000000000..cd0af4b7737
--- /dev/null
+++ b/libstdc++-v3/testsuite/experimental/net/executor/1.cc
@@ -0,0 +1,100 @@
+// Copyright (C) 2020 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run { target c++14 } }
+
+#include <experimental/executor>
+#include <testsuite_hooks.h>
+
+namespace net = std::experimental::net;
+
+void
+test01()
+{
+  net::executor e;
+  VERIFY( !e );
+  VERIFY( e == nullptr );
+  VERIFY( nullptr == e );
+  VERIFY( e == e );
+  VERIFY( e == e );
+  net::executor e2;
+  VERIFY( e == e2 );
+  swap(e, e2);
+  VERIFY( e == e2 );
+  e = e2;
+  VERIFY( e == e2 );
+}
+
+void
+test02()
+{
+  struct E
+  {
+    void on_work_started() const noexcept { }
+    void on_work_finished() const noexcept { }
+    net::execution_context& context() const noexcept { return c; }
+    void dispatch(std::function<void()>, std::allocator<void>) const { }
+    void post(std::function<void()>, std::allocator<void>) const { }
+    void defer(std::function<void()>, std::allocator<void>) const { }
+
+    net::execution_context& c;
+
+    bool operator==(const E& rhs) const noexcept
+    { return &c == &rhs.c; }
+  };
+
+  net::execution_context c;
+  E d{c};
+  net::executor e(d);
+  VERIFY( e == e );
+  VERIFY( e != nullptr );
+  VERIFY( nullptr != e );
+
+  VERIFY( &e.context() == &c );
+#if __cpp_rtti
+  VERIFY( e.target_type() == typeid(E) );
+#endif
+  VERIFY( *e.target<E>() == d );
+  VERIFY( *e.target<const E>() == d );
+  VERIFY( *const_cast<const net::executor&>(e).target<E>() == d );
+  VERIFY( *const_cast<const net::executor&>(e).target<const E>() == d );
+
+  net::executor f = e;
+  VERIFY( f == e );
+  e = nullptr;
+  VERIFY( f != e );
+  swap(e, f);
+  VERIFY( f == nullptr );
+  VERIFY( nullptr != e );
+
+  net::executor g(E{c});
+  VERIFY( e == g );
+}
+
+void
+test03()
+{
+  static_assert( ! std::is_default_constructible<net::system_context>::value, "" );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}