[gcc r11-2759] libstdc++: assert that type traits are not misused with incomplete types [PR 71579]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:69f571ffc513b689fa26e4c9fceba17c2c989ab3

commit r11-2759-g69f571ffc513b689fa26e4c9fceba17c2c989ab3
Author: Antony Polukhin <antoshkka@gmail.com>
Date:   Wed Aug 19 12:10:57 2020 +0100

    libstdc++: assert that type traits are not misused with incomplete types [PR 71579]
    
    libstdc++-v3/ChangeLog:
    
    2020-08-19  Antony Polukhin  <antoshkka@gmail.com>
    
            PR libstdc++/71579
            * include/std/type_traits (invoke_result, is_nothrow_invocable_r)
            Add static_asserts to make sure that the argument of the type
            trait is not misused with incomplete types.
            (is_swappable_with, is_nothrow_swappable_with): Add static_asserts
            to make sure that the first and second arguments of the type trait
            are not misused with incomplete types.
            * testsuite/20_util/invoke_result/incomplete_neg.cc: New test.
            * testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc: New test.
            * testsuite/20_util/is_nothrow_swappable/incomplete_neg.cc: New test.
            * testsuite/20_util/is_nothrow_swappable_with/incomplete_neg.cc: New
            test.
            * testsuite/20_util/is_swappable_with/incomplete_neg.cc: New test.

Diff:
---
 libstdc++-v3/include/std/type_traits               | 24 +++++++++++++---
 .../20_util/invoke_result/incomplete_neg.cc        | 30 ++++++++++++++++++++
 .../20_util/is_nothrow_invocable/incomplete_neg.cc | 33 ++++++++++++++++++++++
 .../20_util/is_nothrow_swappable/incomplete_neg.cc | 29 +++++++++++++++++++
 .../is_nothrow_swappable_with/incomplete_neg.cc    | 31 ++++++++++++++++++++
 .../20_util/is_swappable_with/incomplete_neg.cc    | 31 ++++++++++++++++++++
 6 files changed, 174 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 426febccdf9..62f11902790 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -2811,13 +2811,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp, typename _Up>
     struct is_swappable_with
     : public __is_swappable_with_impl<_Tp, _Up>::type
-    { };
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"first template argument must be a complete class or an unbounded array");
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
+	"second template argument must be a complete class or an unbounded array");
+    };
 
   /// is_nothrow_swappable_with
   template<typename _Tp, typename _Up>
     struct is_nothrow_swappable_with
     : public __is_nothrow_swappable_with_impl<_Tp, _Up>::type
-    { };
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
+	"first template argument must be a complete class or an unbounded array");
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Up>{}),
+	"second template argument must be a complete class or an unbounded array");
+    };
 
 #if __cplusplus >= 201402L
   /// is_swappable_with_v
@@ -2952,7 +2962,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Functor, typename... _ArgTypes>
     struct invoke_result
     : public __invoke_result<_Functor, _ArgTypes...>
-    { };
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Functor>{}),
+	"_Functor must be a complete class or an unbounded array");
+    };
 
   /// std::invoke_result_t
   template<typename _Fn, typename... _Args>
@@ -3001,7 +3014,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct is_nothrow_invocable_r
     : __and_<__is_nt_invocable_impl<__invoke_result<_Fn, _ArgTypes...>, _Ret>,
              __call_is_nothrow_<_Fn, _ArgTypes...>>::type
-    { };
+    {
+      static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
+	"_Fn must be a complete class or an unbounded array");
+    };
 
   /// std::is_invocable_v
   template<typename _Fn, typename... _Args>
diff --git a/libstdc++-v3/testsuite/20_util/invoke_result/incomplete_neg.cc b/libstdc++-v3/testsuite/20_util/invoke_result/incomplete_neg.cc
new file mode 100644
index 00000000000..da58a8beadd
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/invoke_result/incomplete_neg.cc
@@ -0,0 +1,30 @@
+// { dg-do compile { target c++17 } }
+
+// 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-error "must be a complete class" "" { target *-*-* } 0 }
+
+#include <type_traits>
+
+class X;
+
+void test01()
+{
+  std::invoke_result<X, int>();		// { dg-error "required from here" }
+  std::invoke_result<X>();		// { dg-error "required from here" }
+}
diff --git a/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
new file mode 100644
index 00000000000..ad16809027a
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_invocable/incomplete_neg.cc
@@ -0,0 +1,33 @@
+// { dg-do compile { target c++17 } }
+
+// 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-error "must be a complete class" "" { target *-*-* } 0 }
+
+#include <type_traits>
+
+class X;
+
+void test01()
+{
+  std::is_nothrow_invocable<X>();		// { dg-error "required from here" }
+  std::is_nothrow_invocable<X, short>();		// { dg-error "required from here" }
+
+  std::is_nothrow_invocable_r<int, X>();		// { dg-error "required from here" }
+  std::is_nothrow_invocable_r<int, X, short>();		// { dg-error "required from here" }
+}
diff --git a/libstdc++-v3/testsuite/20_util/is_nothrow_swappable/incomplete_neg.cc b/libstdc++-v3/testsuite/20_util/is_nothrow_swappable/incomplete_neg.cc
new file mode 100644
index 00000000000..4a6261d6681
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_swappable/incomplete_neg.cc
@@ -0,0 +1,29 @@
+// { dg-do compile { target c++17 } }
+
+// 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-error "must be a complete class" "" { target *-*-* } 0 }
+
+#include <type_traits>
+
+class X;
+
+void test01()
+{
+  std::is_nothrow_swappable<X>();		// { dg-error "required from here" }
+}
diff --git a/libstdc++-v3/testsuite/20_util/is_nothrow_swappable_with/incomplete_neg.cc b/libstdc++-v3/testsuite/20_util/is_nothrow_swappable_with/incomplete_neg.cc
new file mode 100644
index 00000000000..2fb19de7f52
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/is_nothrow_swappable_with/incomplete_neg.cc
@@ -0,0 +1,31 @@
+// { dg-do compile { target c++17 } }
+
+// 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-error "must be a complete class" "" { target *-*-* } 0 }
+
+#include <type_traits>
+
+class X;
+
+void test01()
+{
+  std::is_nothrow_swappable_with<X, int>();		// { dg-error "required from here" }
+  std::is_nothrow_swappable_with<int, X>();		// { dg-error "required from here" }
+  std::is_nothrow_swappable_with<X, X>();		// { dg-error "required from here" }
+}
diff --git a/libstdc++-v3/testsuite/20_util/is_swappable_with/incomplete_neg.cc b/libstdc++-v3/testsuite/20_util/is_swappable_with/incomplete_neg.cc
new file mode 100644
index 00000000000..dafa4f770ef
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/is_swappable_with/incomplete_neg.cc
@@ -0,0 +1,31 @@
+// { dg-do compile { target c++17 } }
+
+// 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-error "must be a complete class" "" { target *-*-* } 0 }
+
+#include <type_traits>
+
+class X;
+
+void test01()
+{
+  std::is_swappable_with<X, int>();		// { dg-error "required from here" }
+  std::is_swappable_with<int, X>();		// { dg-error "required from here" }
+  std::is_swappable_with<X, X>();		// { dg-error "required from here" }
+}