Fix handling of arrays in range access customization points

This combines the overloads for arrays with the non-array overloads,
using if-constexpr to choose between the cases, and also enforces the
following:

- ADL should only be used for class types and enumeration types.
- ranges::begin should be ill-formed for rvalue arrays.
- ranges::end should be ill-formed for rvalue arrays, unbounded
  arrays, and arrays of incomplete type.
- ranges::size should be ill-formed for unbounded arrays.

	* include/bits/range_access.h (ranges::begin): Combine array and
	non-array overloads into one function template. Only use ADL for
	classes and enums
	(ranges::end, ranges::size): Likewise. Make unbounded arrays
	ill-formed.
	(ranges::rbegin, ranges::rend): Only use ADL for classes and enums.
	Reformat _S_noexcept() functions to mirror operator() structure.
	* testsuite/std/ranges/access/begin.cc: Check incomplete array.
	* testsuite/std/ranges/access/end_neg.cc: New test.
	* testsuite/std/ranges/access/size.cc: Check array of incomplete type.
	* testsuite/std/ranges/access/size_neg.cc: New test.

From-SVN: r277666

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 78ea4476ebed7b150d08fc173b97a87b54a47621..542a350159287a81a3164c4d27cc5602726402b5 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,17 @@
 2019-10-31  Jonathan Wakely  <jwakely@redhat.com>
 
+       * include/bits/range_access.h (ranges::begin): Combine array and
+       non-array overloads into one function template. Only use ADL for
+       classes and enums.
+       (ranges::end, ranges::size): Likewise. Make unbounded arrays
+       ill-formed.
+       (ranges::rbegin, ranges::rend): Only use ADL for classes and enums.
+       Reformat _S_noexcept() functions to mirror operator() structure.
+       * testsuite/std/ranges/access/begin.cc: Check incomplete array.
+       * testsuite/std/ranges/access/end_neg.cc: New test.
+       * testsuite/std/ranges/access/size.cc: Check array of incomplete type.
+       * testsuite/std/ranges/access/size_neg.cc: New test.
+
        * testsuite/24_iterators/range_access*.cc: Move to ...
        * testsuite/24_iterators/range_access/range_access*.cc: ... here.
        * testsuite/24_iterators/range_access/range_access_cpp20_neg.cc: New

diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h
index 9c8bef6b3a198a546332533c02646e3a543edd97..f0a339277e9fb6ef39049aa5148836ac81718d63 100644 (file)
--- a/libstdc++-v3/include/bits/range_access.h
+++ b/libstdc++-v3/include/bits/range_access.h
@@ -391,15 +391,14 @@ namespace ranges
     template<typename _Tp> void begin(initializer_list<_Tp>&&) = delete;
 
     template<typename _Tp>
-      concept __adl_begin = requires(_Tp&& __t)
+      concept __adl_begin
+       = std::__detail::__class_or_enum<remove_reference_t<_Tp>>
+       && requires(_Tp&& __t)
        {
          { __decay_copy(begin(std::forward<_Tp>(__t))) }
            -> input_or_output_iterator;
        };
 
-    template<typename _Tp>
-      concept __complete_type = requires(_Tp* __p) { __p + 1; };
-
     struct _Begin
     {
     private:
@@ -407,23 +406,27 @@ namespace ranges
        static constexpr bool
        _S_noexcept()
        {
-         if constexpr (__member_begin<_Tp>)
+         if constexpr (is_array_v<remove_reference_t<_Tp>>)
+           return true;
+         else if constexpr (__member_begin<_Tp>)
            return noexcept(__decay_copy(std::declval<_Tp>().begin()));
          else
            return noexcept(__decay_copy(begin(std::declval<_Tp>())));
        }
 
     public:
-      template<__complete_type _Tp, size_t _Nm>
-       constexpr _Tp*
-       operator()(_Tp (&__e)[_Nm]) const noexcept
-       { return __e; }
-
-      template<typename _Tp> requires __member_begin<_Tp> || __adl_begin<_Tp>
+      template<typename _Tp>
+       requires is_array_v<remove_reference_t<_Tp>> || __member_begin<_Tp>
+         || __adl_begin<_Tp>
        constexpr auto
        operator()(_Tp&& __e) const noexcept(_S_noexcept<_Tp>())
        {
-         if constexpr (__member_begin<_Tp>)
+         if constexpr (is_array_v<remove_reference_t<_Tp>>)
+           {
+             static_assert(is_lvalue_reference_v<_Tp>);
+             return __e;
+           }
+         else if constexpr (__member_begin<_Tp>)
            return __e.begin();
          else
            return begin(std::forward<_Tp>(__e));
@@ -442,7 +445,9 @@ namespace ranges
     template<typename _Tp> void end(initializer_list<_Tp>&&) = delete;
 
     template<typename _Tp>
-      concept __adl_end = requires(_Tp&& __t)
+      concept __adl_end
+       = std::__detail::__class_or_enum<remove_reference_t<_Tp>>
+       && requires(_Tp&& __t)
        {
          { __decay_copy(end(std::forward<_Tp>(__t))) }
            -> sentinel_for<decltype(_Begin{}(std::forward<_Tp>(__t)))>;
@@ -455,23 +460,28 @@ namespace ranges
        static constexpr bool
        _S_noexcept()
        {
-         if constexpr (__member_end<_Tp>)
+         if constexpr (is_array_v<remove_reference_t<_Tp>>)
+           return true;
+         else if constexpr (__member_end<_Tp>)
            return noexcept(__decay_copy(std::declval<_Tp>().end()));
          else
            return noexcept(__decay_copy(end(std::declval<_Tp>())));
        }
 
     public:
-      template<__complete_type _Tp, size_t _Nm>
-       constexpr _Tp*
-       operator()(_Tp (&__e)[_Nm]) const noexcept
-       { return __e + _Nm; }
-
-      template<typename _Tp> requires __member_end<_Tp> || __adl_end<_Tp>
+      template<typename _Tp>
+       requires is_array_v<remove_reference_t<_Tp>> || __member_end<_Tp>
+       || __adl_end<_Tp>
        constexpr auto
        operator()(_Tp&& __e) const noexcept(_S_noexcept<_Tp>())
        {
-         if constexpr (__member_end<_Tp>)
+         if constexpr (is_array_v<remove_reference_t<_Tp>>)
+           {
+             static_assert(is_lvalue_reference_v<_Tp>);
+             static_assert(is_bounded_array_v<remove_reference_t<_Tp>>);
+             return __e + extent_v<remove_reference_t<_Tp>>;
+           }
+         else if constexpr (__member_end<_Tp>)
            return __e.end();
          else
            return end(std::forward<_Tp>(__e));
@@ -520,7 +530,9 @@ namespace ranges
     template<typename _Tp> void rbegin(_Tp&&) = delete;
 
     template<typename _Tp>
-      concept __adl_rbegin = requires(_Tp&& __t)
+      concept __adl_rbegin
+       = std::__detail::__class_or_enum<remove_reference_t<_Tp>>
+       && requires(_Tp&& __t)
        {
          { __decay_copy(rbegin(std::forward<_Tp>(__t))) }
            -> input_or_output_iterator;
@@ -545,14 +557,17 @@ namespace ranges
            return noexcept(__decay_copy(std::declval<_Tp>().rbegin()));
          else if constexpr (__adl_rbegin<_Tp>)
            return noexcept(__decay_copy(rbegin(std::declval<_Tp>())));
-         else if constexpr (noexcept(_End{}(std::declval<_Tp>())))
+         else
            {
-             using _It = decltype(_End{}(std::declval<_Tp>()));
-             // std::reverse_iterator copy-initializes its member.
-             return is_nothrow_copy_constructible_v<_It>;
+             if constexpr (noexcept(_End{}(std::declval<_Tp>())))
+               {
+                 using _It = decltype(_End{}(std::declval<_Tp>()));
+                 // std::reverse_iterator copy-initializes its member.
+                 return is_nothrow_copy_constructible_v<_It>;
+               }
+             else
+               return false;
            }
-         else
-           return false;
        }
 
     public:
@@ -582,7 +597,9 @@ namespace ranges
     template<typename _Tp> void rend(_Tp&&) = delete;
 
     template<typename _Tp>
-      concept __adl_rend = requires(_Tp&& __t)
+      concept __adl_rend
+       = std::__detail::__class_or_enum<remove_reference_t<_Tp>>
+       && requires(_Tp&& __t)
        {
          { __decay_copy(rend(std::forward<_Tp>(__t))) }
            -> sentinel_for<decltype(_RBegin{}(std::forward<_Tp>(__t)))>;
@@ -599,14 +616,17 @@ namespace ranges
            return noexcept(__decay_copy(std::declval<_Tp>().rend()));
          else if constexpr (__adl_rend<_Tp>)
            return noexcept(__decay_copy(rend(std::declval<_Tp>())));
-         else if constexpr (noexcept(_Begin{}(std::declval<_Tp>())))
+         else
            {
-             using _It = decltype(_Begin{}(std::declval<_Tp>()));
-             // std::reverse_iterator copy-initializes its member.
-             return is_nothrow_copy_constructible_v<_It>;
+             if constexpr (noexcept(_Begin{}(std::declval<_Tp>())))
+               {
+                 using _It = decltype(_Begin{}(std::declval<_Tp>()));
+                 // std::reverse_iterator copy-initializes its member.
+                 return is_nothrow_copy_constructible_v<_It>;
+               }
+             else
+               return false;
            }
-         else
-           return false;
        }
 
     public:
@@ -660,7 +680,9 @@ namespace ranges
     template<typename _Tp> void size(_Tp&&) = delete;
 
     template<typename _Tp>
-      concept __adl_size = !disable_sized_range<remove_cvref_t<_Tp>>
+      concept __adl_size
+       = std::__detail::__class_or_enum<remove_reference_t<_Tp>>
+       && !disable_sized_range<remove_cvref_t<_Tp>>
        && requires(_Tp&& __t)
        {
          { __decay_copy(size(std::forward<_Tp>(__t))) }
@@ -689,7 +711,9 @@ namespace ranges
        static constexpr bool
        _S_noexcept()
        {
-         if constexpr (__member_size<_Tp>)
+         if constexpr (is_array_v<remove_reference_t<_Tp>>)
+           return true;
+         else if constexpr (__member_size<_Tp>)
            return noexcept(__decay_copy(std::declval<_Tp>().size()));
          else if constexpr (__adl_size<_Tp>)
            return noexcept(__decay_copy(size(std::declval<_Tp>())));
@@ -699,17 +723,18 @@ namespace ranges
        }
 
     public:
-      template<__complete_type _Tp, size_t _Nm>
-       constexpr size_t
-       operator()(_Tp (&__e)[_Nm]) const noexcept
-       { return _Nm; }
-
       template<typename _Tp>
-       requires __member_size<_Tp> || __adl_size<_Tp> || __sizable<_Tp>
+       requires is_array_v<remove_reference_t<_Tp>>
+         || __member_size<_Tp> || __adl_size<_Tp> || __sizable<_Tp>
        constexpr auto
        operator()(_Tp&& __e) const noexcept(_S_noexcept<_Tp>())
        {
-         if constexpr (__member_size<_Tp>)
+         if constexpr (is_array_v<remove_reference_t<_Tp>>)
+           {
+             static_assert(is_bounded_array_v<remove_reference_t<_Tp>>);
+             return extent_v<remove_reference_t<_Tp>>;
+           }
+         else if constexpr (__member_size<_Tp>)
            return std::forward<_Tp>(__e).size();
          else if constexpr (__adl_size<_Tp>)
            return size(std::forward<_Tp>(__e));

diff --git a/libstdc++-v3/testsuite/std/ranges/access/begin.cc b/libstdc++-v3/testsuite/std/ranges/access/begin.cc
index 1d7db46b68a285d3bf82192d5083131cd0b21229..100dcf69c6ec8538aa0958f2133b0bb55b1931a0 100644 (file)
--- a/libstdc++-v3/testsuite/std/ranges/access/begin.cc
+++ b/libstdc++-v3/testsuite/std/ranges/access/begin.cc
@@ -35,6 +35,11 @@ test01()
 
   constexpr long b[2] = { };
   static_assert( std::ranges::begin(b) == (b + 0) );
+
+  struct Incomplete;
+  using A = Incomplete[]; // unbounded array of incomplete type
+  extern A& f();
+  static_assert( same_as<decltype(std::ranges::begin(f())), Incomplete*> );
 }
 
 void

diff --git a/libstdc++-v3/testsuite/std/ranges/access/end_neg.cc b/libstdc++-v3/testsuite/std/ranges/access/end_neg.cc
new file mode 100644 (file)
index 0000000..a2a8fb0
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/ranges/access/end_neg.cc
@@ -0,0 +1,42 @@
+// Copyright (C) 2019 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++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <iterator> // N.B. should be <ranges>
+
+extern int unbounded[];
+
+auto
+test01()
+{
+  return std::ranges::end(unbounded); // { dg-error "here" }
+}
+// { dg-error "static assertion failed" "" { target *-*-* } 0 }
+
+struct incomplete;
+extern incomplete array[2];
+
+auto
+test02()
+{
+  return std::ranges::end(array); // { dg-error "here" }
+}
+// { dg-error "incomplete type" "" { target *-*-* } 0 }
+
+

diff --git a/libstdc++-v3/testsuite/std/ranges/access/size.cc b/libstdc++-v3/testsuite/std/ranges/access/size.cc
index b92e5d504497816470e7849df64f39955b2c728b..b0a27ca2a8746337370ebcc46df91dfafef9d1fd 100644 (file)
--- a/libstdc++-v3/testsuite/std/ranges/access/size.cc
+++ b/libstdc++-v3/testsuite/std/ranges/access/size.cc
@@ -32,6 +32,11 @@ test01()
   int a2[2];
   VERIFY( std::ranges::size(a2) == 2);
   static_assert( noexcept(std::ranges::size(a2)) );
+
+  struct Incomplete;
+  using A = Incomplete[2]; // bounded array of incomplete type
+  extern A& f();
+  static_assert( std::same_as<decltype(std::ranges::size(f())), std::size_t> );
 }
 
 void
@@ -84,8 +89,7 @@ test04()
 {
   int a[] = { 0, 1 };
   __gnu_test::test_range<int, __gnu_test::random_access_iterator_wrapper> r(a);
-  auto& rr = r;
-  VERIFY( std::ranges::size(r) == (std::ranges::end(r) - std::ranges::begin(r)) );
+  VERIFY( std::ranges::size(r) == unsigned(std::ranges::end(r) - std::ranges::begin(r)) );
 }
 
 struct R5

diff --git a/libstdc++-v3/testsuite/std/ranges/access/size_neg.cc b/libstdc++-v3/testsuite/std/ranges/access/size_neg.cc
new file mode 100644 (file)
index 0000000..0ba8d81
--- /dev/null
+++ b/libstdc++-v3/testsuite/std/ranges/access/size_neg.cc
@@ -0,0 +1,30 @@
+// Copyright (C) 2019 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++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <iterator> // N.B. should be <ranges>
+
+extern int unbounded[];
+
+auto
+test01()
+{
+  return std::ranges::size(unbounded); // { dg-error "here" }
+}
+// { dg-error "static assertion failed" "" { target *-*-* } 0 }