[PATCH] LWG 2733, LWG 2759 reject bool in gcd and lcm

[PATCH] LWG 2733, LWG 2759 reject bool in gcd and lcm

[Jonathan Wakely]

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These DRs are only in Tentatively Ready status, but they're not
controversial so implementing them immediately seems sensible.

The deleted function is sufficient, but the static assertions are more
user-friendly (and are only tested once, not in every recursive call
to __gcd or __lcm).

	* include/experimental/numeric (gcd, lcm): Make bool arguments
	ill-formed.
	* include/std/numeric (gcd, lcm): Likewise.
	* testsuite/26_numerics/gcd/gcd_neg.cc: New test.
	* testsuite/26_numerics/lcm/lcm_neg.cc: New test.

Tested x86_64-linux, committed to trunk.


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commit a785026d8d928a1492daf6919a57d6cda714f714
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon Oct 10 11:58:27 2016 +0100

    LWG 2733, LWG 2759 reject bool in gcd and lcm
    
    	* include/experimental/numeric (gcd, lcm): Make bool arguments
    	ill-formed.
    	* include/std/numeric (gcd, lcm): Likewise.
    	* testsuite/26_numerics/gcd/gcd_neg.cc: New test.
    	* testsuite/26_numerics/lcm/lcm_neg.cc: New test.

diff --git a/libstdc++-v3/include/experimental/numeric b/libstdc++-v3/include/experimental/numeric
index 6d1dc21..0ce4bda 100644
--- a/libstdc++-v3/include/experimental/numeric
+++ b/libstdc++-v3/include/experimental/numeric
@@ -57,8 +57,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     constexpr common_type_t<_Mn, _Nn>
     gcd(_Mn __m, _Nn __n)
     {
-      static_assert(is_integral<_Mn>::value, "arguments to gcd are integers");
-      static_assert(is_integral<_Nn>::value, "arguments to gcd are integers");
+      static_assert(is_integral<_Mn>::value, "gcd arguments are integers");
+      static_assert(is_integral<_Nn>::value, "gcd arguments are integers");
+      static_assert(!is_same<_Mn, bool>::value, "gcd arguments are not bools");
+      static_assert(!is_same<_Nn, bool>::value, "gcd arguments are not bools");
       return std::__detail::__gcd(__m, __n);
     }
 
@@ -67,8 +69,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     constexpr common_type_t<_Mn, _Nn>
     lcm(_Mn __m, _Nn __n)
     {
-      static_assert(is_integral<_Mn>::value, "arguments to lcm are integers");
-      static_assert(is_integral<_Nn>::value, "arguments to lcm are integers");
+      static_assert(is_integral<_Mn>::value, "lcm arguments are integers");
+      static_assert(is_integral<_Nn>::value, "lcm arguments are integers");
+      static_assert(!is_same<_Mn, bool>::value, "lcm arguments are not bools");
+      static_assert(!is_same<_Nn, bool>::value, "lcm arguments are not bools");
       return std::__detail::__lcm(__m, __n);
     }
 
diff --git a/libstdc++-v3/include/std/numeric b/libstdc++-v3/include/std/numeric
index 7b1ab98..4414081 100644
--- a/libstdc++-v3/include/std/numeric
+++ b/libstdc++-v3/include/std/numeric
@@ -96,6 +96,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     __abs_integral(_Tp __val)
     { return __val; }
 
+  void __abs_integral(bool) = delete;
+
   template<typename _Mn, typename _Nn>
     constexpr common_type_t<_Mn, _Nn>
     __gcd(_Mn __m, _Nn __n)
@@ -129,8 +131,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     constexpr common_type_t<_Mn, _Nn>
     gcd(_Mn __m, _Nn __n)
     {
-      static_assert(is_integral<_Mn>::value, "arguments to gcd are integers");
-      static_assert(is_integral<_Nn>::value, "arguments to gcd are integers");
+      static_assert(is_integral<_Mn>::value, "gcd arguments are integers");
+      static_assert(is_integral<_Nn>::value, "gcd arguments are integers");
+      static_assert(!is_same<_Mn, bool>::value, "gcd arguments are not bools");
+      static_assert(!is_same<_Nn, bool>::value, "gcd arguments are not bools");
       return __detail::__gcd(__m, __n);
     }
 
@@ -140,8 +144,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     constexpr common_type_t<_Mn, _Nn>
     lcm(_Mn __m, _Nn __n)
     {
-      static_assert(is_integral<_Mn>::value, "arguments to lcm are integers");
-      static_assert(is_integral<_Nn>::value, "arguments to lcm are integers");
+      static_assert(is_integral<_Mn>::value, "lcm arguments are integers");
+      static_assert(is_integral<_Nn>::value, "lcm arguments are integers");
+      static_assert(!is_same<_Mn, bool>::value, "lcm arguments are not bools");
+      static_assert(!is_same<_Nn, bool>::value, "lcm arguments are not bools");
       return __detail::__lcm(__m, __n);
     }
 
diff --git a/libstdc++-v3/testsuite/26_numerics/gcd/gcd_neg.cc b/libstdc++-v3/testsuite/26_numerics/gcd/gcd_neg.cc
new file mode 100644
index 0000000..231ce8d
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/gcd/gcd_neg.cc
@@ -0,0 +1,39 @@
+// Copyright (C) 2016 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++1z" }
+// { dg-do compile { target c++1z } }
+
+#include <numeric>
+
+void
+test01()
+{
+  std::gcd(true, 1);    // { dg-error "from here" }
+  std::gcd(1, true);    // { dg-error "from here" }
+  std::gcd(true, true); // { dg-error "from here" }
+  std::gcd(0.1, 1);     // { dg-error "from here" }
+  std::gcd(1, 0.1);     // { dg-error "from here" }
+  std::gcd(0.1, 0.1);   // { dg-error "from here" }
+}
+
+// { dg-error "integers" "" { target *-*-* } 134 }
+// { dg-error "integers" "" { target *-*-* } 135 }
+// { dg-error "not bools" "" { target *-*-* } 136 }
+// { dg-error "not bools" "" { target *-*-* } 137 }
+// { dg-prune-output "deleted function" }
+// { dg-prune-output "invalid operands" }
diff --git a/libstdc++-v3/testsuite/26_numerics/lcm/lcm_neg.cc b/libstdc++-v3/testsuite/26_numerics/lcm/lcm_neg.cc
new file mode 100644
index 0000000..085ad77
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/lcm/lcm_neg.cc
@@ -0,0 +1,39 @@
+// Copyright (C) 2016 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++1z" }
+// { dg-do compile { target c++1z } }
+
+#include <numeric>
+
+void
+test01()
+{
+  std::lcm(true, 1);    // { dg-error "from here" }
+  std::lcm(1, true);    // { dg-error "from here" }
+  std::lcm(true, true); // { dg-error "from here" }
+  std::lcm(0.1, 1);     // { dg-error "from here" }
+  std::lcm(1, 0.1);     // { dg-error "from here" }
+  std::lcm(0.1, 0.1);   // { dg-error "from here" }
+}
+
+// { dg-error "integers" "" { target *-*-* } 147 }
+// { dg-error "integers" "" { target *-*-* } 148 }
+// { dg-error "not bools" "" { target *-*-* } 149 }
+// { dg-error "not bools" "" { target *-*-* } 150 }
+// { dg-prune-output "deleted function" }
+// { dg-prune-output "invalid operands" }