From 5db25ab107e93e63ab6a0cb8e8f376c234118d1e Mon Sep 17 00:00:00 2001
From: Daniel Krugler <daniel.kruegler@googlemail.com>
Date: Mon, 21 Nov 2011 11:21:13 +0000
Subject: [PATCH] re PR libstdc++/51185 ([C++0x] false-positive results of
std::is_constructible)
2011-11-21 Daniel Krugler <daniel.kruegler@googlemail.com>
PR libstdc++/51185
* include/std/type_traits (__is_base_to_derived_ref,
__is_lvalue_to_rvalue_ref): Fix.
* testsuite/20_util/is_constructible/51185.cc: New.
* testsuite/20_util/is_constructible/value-2.cc: Extend.
From-SVN: r181557
---
libstdc++-v3/ChangeLog | 8 ++++
libstdc++-v3/include/std/type_traits | 22 ++++++++---
.../20_util/declval/requirements/1_neg.cc | 2 +-
.../20_util/is_constructible/51185.cc | 39 +++++++++++++++++++
.../20_util/is_constructible/value-2.cc | 2 +
.../make_signed/requirements/typedefs_neg.cc | 4 +-
.../requirements/typedefs_neg.cc | 4 +-
7 files changed, 70 insertions(+), 11 deletions(-)
create mode 100644 libstdc++-v3/testsuite/20_util/is_constructible/51185.cc
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 9689052ab664..81a4ac8c9471 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,11 @@
+2011-11-21 Daniel Krugler <daniel.kruegler@googlemail.com>
+
+ PR libstdc++/51185
+ * include/std/type_traits (__is_base_to_derived_ref,
+ __is_lvalue_to_rvalue_ref): Fix.
+ * testsuite/20_util/is_constructible/51185.cc: New.
+ * testsuite/20_util/is_constructible/value-2.cc: Extend.
+
2011-11-21 Paolo Carlini <paolo.carlini@oracle.com>
* include/std/tuple (__conv_types, __one_by_one_convertible,
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index a0208590bb56..46e3f800caba 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -745,6 +745,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Implementation for non-reference types. To meet the proper
// variable definition semantics, we also need to test for
// is_destructible in this case.
+ // This form should be simplified by a single expression:
+ // ::delete ::new _Tp(declval<_Arg>()), see c++/51222.
struct __do_is_direct_constructible_impl
{
template<typename _Tp, typename _Arg, typename
@@ -778,9 +780,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
struct remove_reference;
template<typename _From, typename _To, bool
- = is_reference<_From>::value>
+ = __not_<__or_<is_void<_From>,
+ is_function<_From>>>::value>
struct __is_base_to_derived_ref;
+ // Detect whether we have a downcast situation during
+ // reference binding.
template<typename _From, typename _To>
struct __is_base_to_derived_ref<_From, _To, true>
{
@@ -803,6 +808,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
is_rvalue_reference<_To>>::value>
struct __is_lvalue_to_rvalue_ref;
+ // Detect whether we have an lvalue of non-function type
+ // bound to a reference-compatible rvalue-reference.
template<typename _From, typename _To>
struct __is_lvalue_to_rvalue_ref<_From, _To, true>
{
@@ -810,8 +817,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_From>::type>::type __src_t;
typedef typename remove_cv<typename remove_reference<
_To>::type>::type __dst_t;
- typedef __or_<is_same<__src_t, __dst_t>,
- is_base_of<__dst_t, __src_t>> type;
+ typedef __and_<__not_<is_function<__src_t>>,
+ __or_<is_same<__src_t, __dst_t>,
+ is_base_of<__dst_t, __src_t>>> type;
static constexpr bool value = type::value;
};
@@ -823,9 +831,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Here we handle direct-initialization to a reference type as
// equivalent to a static_cast modulo overshooting conversions.
// These are restricted to the following conversions:
- // a) A glvalue of a base class to a derived class reference
+ // a) A base class value to a derived class reference
// b) An lvalue to an rvalue-reference of reference-compatible
- // types
+ // types that are not functions
template<typename _Tp, typename _Arg>
struct __is_direct_constructible_ref_cast
: public __and_<__is_static_castable<_Arg, _Tp>,
@@ -850,7 +858,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Since default-construction and binary direct-initialization have
// been handled separately, the implementation of the remaining
- // n-ary construction cases is rather straightforward.
+ // n-ary construction cases is rather straightforward. We can use
+ // here a functional cast, because array types are excluded anyway
+ // and this form is never interpreted as a C cast.
struct __do_is_nary_constructible_impl
{
template<typename _Tp, typename... _Args, typename
diff --git a/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc b/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
index 1f4065b92a85..33ab45b4bbcb 100644
--- a/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
@@ -19,7 +19,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
-// { dg-error "static assertion failed" "" { target *-*-* } 1759 }
+// { dg-error "static assertion failed" "" { target *-*-* } 1769 }
#include <utility>
diff --git a/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc b/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc
new file mode 100644
index 000000000000..faf3969fe83d
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/is_constructible/51185.cc
@@ -0,0 +1,39 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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/>.
+
+#include <type_traits>
+
+struct A { };
+struct B : A { };
+
+// libstdc++/51185
+void f()
+{
+ static_assert(!std::is_constructible<B &&, A>(), "");
+ static_assert(!std::is_constructible<B const &&, A>(), "");
+ static_assert(!std::is_constructible<B const &&, A const>(), "");
+ static_assert(!std::is_constructible<B volatile &&, A>(), "");
+ static_assert(!std::is_constructible<B volatile &&, A volatile>(), "");
+ static_assert(!std::is_constructible<B const volatile &&, A>(), "");
+ static_assert(!std::is_constructible<B const volatile &&, A const>(), "");
+ static_assert(!std::is_constructible<B const volatile &&, A volatile>(), "");
+ static_assert(!std::is_constructible<B const volatile &&,
+ A const volatile>(), "");
+}
diff --git a/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc b/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc
index 24fde9389887..06895e32bb0a 100644
--- a/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc
+++ b/libstdc++-v3/testsuite/20_util/is_constructible/value-2.cc
@@ -817,3 +817,5 @@ static_assert(!std::is_constructible<const int&, ExplicitTo<double&&>>::value,
"Error");
static_assert(!std::is_constructible<int&&, ExplicitTo<double&&>>::value,
"Error");
+
+static_assert(std::is_constructible<void(&&)(), void(&)()>::value, "Error");
diff --git a/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc b/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc
index d61daf358532..b8bd23f841f4 100644
--- a/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/make_signed/requirements/typedefs_neg.cc
@@ -48,5 +48,5 @@ void test01()
// { dg-error "required from here" "" { target *-*-* } 40 }
// { dg-error "required from here" "" { target *-*-* } 42 }
-// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1545 }
-// { dg-error "declaration of" "" { target *-*-* } 1509 }
+// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1555 }
+// { dg-error "declaration of" "" { target *-*-* } 1519 }
diff --git a/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc b/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc
index ee74be9f267f..96940119ed90 100644
--- a/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc
+++ b/libstdc++-v3/testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc
@@ -48,5 +48,5 @@ void test01()
// { dg-error "required from here" "" { target *-*-* } 40 }
// { dg-error "required from here" "" { target *-*-* } 42 }
-// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1463 }
-// { dg-error "declaration of" "" { target *-*-* } 1427 }
+// { dg-error "invalid use of incomplete type" "" { target *-*-* } 1473 }
+// { dg-error "declaration of" "" { target *-*-* } 1437 }
--
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