Make filesystem::file_status default constructor non-explicit (LWG 2787)

	* include/bits/fs_dir.h (file_status): Make default constructor
	non-explicit (LWG 2787).
	* testsuite/27_io/filesystem/file_status/1.cc: New test.
	* testsuite/experimental/filesystem/file_status/1.cc: New test.

From-SVN: r254159

libstdc++-v3/ChangeLog

 2017-10-27  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/bits/fs_dir.h (file_status): Make default constructor
+	non-explicit (LWG 2787).
+	* testsuite/27_io/filesystem/file_status/1.cc: New test.
+	* testsuite/experimental/filesystem/file_status/1.cc: New test.
+
 	* include/std/fstream (basic_filebuf::_If_path): New SFINAE helper.
 	(basic_filebuf::open<Path>(const Path&, const ios_base::openmode&))
 	(basic_ifstream<Path>(const Path&, const ios_base::openmode&))

libstdc++-v3/include/bits/fs_dir.h

@@ -50,10 +50,11 @@ namespace filesystem
   class file_status
   {
   public:
-    // constructors
+    // constructors and destructor
+    file_status() noexcept : file_status(file_type::none) {}
+
     explicit
-    file_status(file_type __ft = file_type::none,
-	        perms __prms = perms::unknown) noexcept
+    file_status(file_type __ft, perms __prms = perms::unknown) noexcept
     : _M_type(__ft), _M_perms(__prms) { }
 
     file_status(const file_status&) noexcept = default;

libstdc++-v3/testsuite/27_io/filesystem/file_status/1.cc

+// Copyright (C) 2017 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-options "-std=gnu++17 -lstdc++fs" }
+// { dg-do run { target c++17 } }
+// { dg-require-filesystem-ts "" }
+
+#include <filesystem>
+#include <testsuite_hooks.h>
+
+namespace fs = std::filesystem;
+
+template<typename... Args>
+constexpr bool nothrow_constructible() {
+  return std::is_nothrow_constructible<fs::file_status, Args...>::value;
+}
+
+void
+test01()
+{
+  fs::file_status st0;
+  VERIFY( st0.type() == fs::file_type::none );
+  VERIFY( st0.permissions() == fs::perms::unknown );
+  static_assert( nothrow_constructible<>(), "" );
+
+  fs::file_status st1(fs::file_type::regular);
+  VERIFY( st1.type() == fs::file_type::regular );
+  VERIFY( st1.permissions() == fs::perms::unknown );
+  static_assert( nothrow_constructible<fs::file_type>(), "" );
+
+  fs::file_status st2(fs::file_type::directory, fs::perms::owner_all);
+  VERIFY( st2.type() == fs::file_type::directory );
+  VERIFY( st2.permissions() == fs::perms::owner_all );
+  static_assert( nothrow_constructible<fs::file_type, fs::perms>(), "" );
+
+  static_assert( nothrow_constructible<const fs::file_status&>(), "" );
+  static_assert( nothrow_constructible<fs::file_status>(), "" );
+}
+
+void
+test02()
+{
+  fs::file_status st;
+  VERIFY( st.type() == fs::file_type::none );
+  VERIFY( st.permissions() == fs::perms::unknown );
+
+  st.type(fs::file_type::symlink);
+  VERIFY( st.type() == fs::file_type::symlink );
+  VERIFY( st.permissions() == fs::perms::unknown );
+
+  st.permissions(fs::perms::owner_all);
+  VERIFY( st.type() == fs::file_type::symlink );
+  VERIFY( st.permissions() == fs::perms::owner_all );
+}
+
+void check_non_explicit_constructor(fs::file_status) { }
+
+void
+test03()
+{
+  check_non_explicit_constructor( {} ); // LWG 2787
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+}

libstdc++-v3/testsuite/experimental/filesystem/file_status/1.cc

+// Copyright (C) 2017 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-options "-lstdc++fs" }
+// { dg-do run { target c++11 } }
+// { dg-require-filesystem-ts "" }
+
+#include <experimental/filesystem>
+#include <testsuite_hooks.h>
+
+namespace fs = std::experimental::filesystem;
+
+template<typename... Args>
+constexpr bool nothrow_constructible() {
+  return std::is_nothrow_constructible<fs::file_status, Args...>::value;
+}
+
+void
+test01()
+{
+  fs::file_status st0;
+  VERIFY( st0.type() == fs::file_type::none );
+  VERIFY( st0.permissions() == fs::perms::unknown );
+  static_assert( nothrow_constructible<>(), "" );
+
+  fs::file_status st1(fs::file_type::regular);
+  VERIFY( st1.type() == fs::file_type::regular );
+  VERIFY( st1.permissions() == fs::perms::unknown );
+  static_assert( nothrow_constructible<fs::file_type>(), "" );
+
+  fs::file_status st2(fs::file_type::directory, fs::perms::owner_all);
+  VERIFY( st2.type() == fs::file_type::directory );
+  VERIFY( st2.permissions() == fs::perms::owner_all );
+  static_assert( nothrow_constructible<fs::file_type, fs::perms>(), "" );
+
+  static_assert( nothrow_constructible<const fs::file_status&>(), "" );
+  static_assert( nothrow_constructible<fs::file_status>(), "" );
+}
+
+void
+test02()
+{
+  fs::file_status st;
+  VERIFY( st.type() == fs::file_type::none );
+  VERIFY( st.permissions() == fs::perms::unknown );
+
+  st.type(fs::file_type::symlink);
+  VERIFY( st.type() == fs::file_type::symlink );
+  VERIFY( st.permissions() == fs::perms::unknown );
+
+  st.permissions(fs::perms::owner_all);
+  VERIFY( st.type() == fs::file_type::symlink );
+  VERIFY( st.permissions() == fs::perms::owner_all );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}