From 127d76c37016f91fcaa5e4618cd1a5d6fa40b087 Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Wed, 10 Jun 2020 17:57:54 +0200
Subject: [PATCH] Fix ambiguous comparisons error with C++20

```
/home/cgal_tester/build/src/cmake/platforms/ArchLinux-clang-CXX20-Release/test/Kernel_d/afftrafo-test.cpp:136:31: error: use of overloaded operator '==' is ambiguous (with operand types 'VectorHd<CGAL::VectorHd<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > >::RT, CGAL::VectorHd<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > >::LA>' (aka 'VectorHd<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > >') and 'Vector_d<CGAL::Homogeneous_d<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > > >')
    CGAL_TEST(v.transform(at9)==3*v){}
              ~~~~~~~~~~~~~~~~^ ~~~
/home/cgal_tester/build/src/cmake/platforms/ArchLinux-clang-CXX20-Release/test/Kernel_d/include/CGAL/test_macros.h:10:28: note: expanded from macro 'CGAL_TEST'
                           ^
/mnt/testsuite/include/CGAL/Kernel_d/VectorHd.h:350:6: note: candidate function
bool operator==(const VectorHd<RT,LA>& w) const
     ^
/mnt/testsuite/include/CGAL/Kernel_d/Vector_d.h:90:8: note: candidate function (with reversed parameter order)
  bool operator==(const Self& w) const
       ^
```

```
/home/cgal_tester/build/src/cmake/platforms/ArchLinux-clang-CXX20-Release/test/Kernel_d/afftrafo-test.cpp:141:33: error: use of overloaded operator '==' is ambiguous (with operand types 'DirectionHd<CGAL::DirectionHd<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > >::RT, CGAL::DirectionHd<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > >::LA>' (aka 'DirectionHd<__gmp_expr<mpz_t, mpz_t>, CGAL::Linear_algebraHd<__gmp_expr<mpz_t, mpz_t>, std::allocator<__gmp_expr<mpz_t, mpz_t> > > >') and 'Direction' (aka 'Direction_d<Homogeneous_d<__gmp_expr<__mpz_struct [1], __mpz_struct [1]> > >'))
    CGAL_TEST(dir.transform(at9)==dir){}
              ~~~~~~~~~~~~~~~~~~^ ~~~
/home/cgal_tester/build/src/cmake/platforms/ArchLinux-clang-CXX20-Release/test/Kernel_d/include/CGAL/test_macros.h:10:28: note: expanded from macro 'CGAL_TEST'
                           ^
/mnt/testsuite/include/CGAL/Kernel_d/DirectionHd.h:181:6: note: candidate function
bool operator==(const DirectionHd<RT,LA>& w) const
     ^
/mnt/testsuite/include/CGAL/Kernel_d/Direction_d.h:61:8: note: candidate function (with reversed parameter order)
  bool operator==(const Self& w) const
       ^
```
---
 Kernel_d/include/CGAL/Kernel_d/Direction_d.h | 4 ++++
 Kernel_d/include/CGAL/Kernel_d/Vector_d.h    | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/Kernel_d/include/CGAL/Kernel_d/Direction_d.h b/Kernel_d/include/CGAL/Kernel_d/Direction_d.h
index 4cef344f845..70bd4c1b725 100644
--- a/Kernel_d/include/CGAL/Kernel_d/Direction_d.h
+++ b/Kernel_d/include/CGAL/Kernel_d/Direction_d.h
@@ -62,6 +62,10 @@ class Direction_d : public pR::Direction_d_base
   { return Base::operator==(w); }
   bool operator!=(const Self& w) const
   { return Base::operator!=(w); }
+  bool operator==(const Base& w) const
+  { return Base::operator==(w); }
+  bool operator!=(const Base& w) const
+  { return Base::operator!=(w); }
 };
 
 } //namespace CGAL
diff --git a/Kernel_d/include/CGAL/Kernel_d/Vector_d.h b/Kernel_d/include/CGAL/Kernel_d/Vector_d.h
index f434e579f6b..ffd79e265ba 100644
--- a/Kernel_d/include/CGAL/Kernel_d/Vector_d.h
+++ b/Kernel_d/include/CGAL/Kernel_d/Vector_d.h
@@ -91,6 +91,10 @@ class Vector_d : public pR::Vector_d_base
   { return Base::operator==(w); }
   bool operator!=(const Self& w) const
   { return Base::operator!=(w); }
+  bool operator==(const Base& w) const
+  { return Base::operator==(w); }
+  bool operator!=(const Base& w) const
+  { return Base::operator!=(w); }
 
 };