Revert r276548 - Make pair/tuples assignment operators SFINAE properly.

This is a breaking change. The SFINAE required is instantiated the second
the class is instantiated, and this can cause hard SFINAE errors
when applied to references to incomplete types. Ex.

struct IncompleteType;
extern IncompleteType it;
std::tuple<IncompleteType&> t(it); // SFINAE will blow up.

llvm-svn: 276598

3 files changed, 2 insertions, 192 deletions

diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
deleted file mode 100644
index d75b6a5f820..00000000000
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
+++ /dev/null
@@ -1,90 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++98, c++03
-
-// <utility>
-
-// template <class T1, class T2> struct pair
-
-// pair& operator=(pair const& p);
-
-#include <utility>
-#include <memory>
-#include <cassert>
-
-
-struct NonAssignable {
-  NonAssignable& operator=(NonAssignable const&) = delete;
-  NonAssignable& operator=(NonAssignable&&) = delete;
-};
-struct CopyAssignable {
-  CopyAssignable() = default;
-  CopyAssignable(CopyAssignable const&) = default;
-  CopyAssignable& operator=(CopyAssignable const&) = default;
-  CopyAssignable& operator=(CopyAssignable&&) = delete;
-};
-struct MoveAssignable {
-  MoveAssignable() = default;
-  MoveAssignable& operator=(MoveAssignable const&) = delete;
-  MoveAssignable& operator=(MoveAssignable&&) = default;
-};
-
-
-struct CountAssign {
-  static int copied;
-  static int moved;
-  static void reset() { copied = moved = 0; }
-  CountAssign() = default;
-  CountAssign& operator=(CountAssign const&) { ++copied; return *this; }
-  CountAssign& operator=(CountAssign&&) { ++moved; return *this; }
-};
-int CountAssign::copied = 0;
-int CountAssign::moved = 0;
-
-int main()
-{
-    {
-        typedef std::pair<CopyAssignable, short> P;
-        const P p1(CopyAssignable(), 4);
-        P p2;
-        p2 = p1;
-        assert(p2.second == 4);
-    }
-    {
-        using P = std::pair<int&, int&&>;
-        int x = 42;
-        int y = 101;
-        int x2 = -1;
-        int y2 = 300;
-        P p1(x, std::move(y));
-        P p2(x2, std::move(y2));
-        p1 = p2;
-        assert(p1.first == x2);
-        assert(p1.second == y2);
-    }
-    {
-        using P = std::pair<int, NonAssignable>;
-        static_assert(!std::is_copy_assignable<P>::value, "");
-    }
-    {
-        CountAssign::reset();
-        using P = std::pair<CountAssign, CopyAssignable>;
-        static_assert(std::is_copy_assignable<P>::value, "");
-        P p;
-        P p2;
-        p = p2;
-        assert(CountAssign::copied == 1);
-        assert(CountAssign::moved == 0);
-    }
-    {
-        using P = std::pair<int, MoveAssignable>;
-        static_assert(!std::is_copy_assignable<P>::value, "");
-    }
-}
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
deleted file mode 100644
index 8b9d1ed8905..00000000000
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
+++ /dev/null
@@ -1,36 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-// REQUIRES-ANY: c++98, c++03
-
-// <utility>
-
-// template <class T1, class T2> struct pair
-
-// pair& operator=(pair const& p);
-
-#include <utility>
-#include <memory>
-#include <cassert>
-
-
-struct NonAssignable {
-  NonAssignable() {}
-private:
-  NonAssignable& operator=(NonAssignable const&);
-};
-
-int main()
-{
-    // Test that we don't constrain the assignment operator in C++03 mode.
-    // Since we don't have access control SFINAE having pair evaluate SFINAE
-    // may cause a hard error.
-    typedef std::pair<int, NonAssignable> P;
-    static_assert(std::is_copy_assignable<P>::value, "");
-}
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
index 38089200e4d..a753ee520df 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
@@ -7,8 +7,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// UNSUPPORTED: c++98, c++03
-
 // <utility>
 
 // template <class T1, class T2> struct pair
@@ -19,35 +17,9 @@
 #include <memory>
 #include <cassert>
 
-
-struct NonAssignable {
-  NonAssignable& operator=(NonAssignable const&) = delete;
-  NonAssignable& operator=(NonAssignable&&) = delete;
-};
-struct CopyAssignable {
-  CopyAssignable() = default;
-  CopyAssignable& operator=(CopyAssignable const&) = default;
-  CopyAssignable& operator=(CopyAssignable&&) = delete;
-};
-struct MoveAssignable {
-  MoveAssignable() = default;
-  MoveAssignable& operator=(MoveAssignable const&) = delete;
-  MoveAssignable& operator=(MoveAssignable&&) = default;
-};
-
-struct CountAssign {
-  static int copied;
-  static int moved;
-  static void reset() { copied = moved = 0; }
-  CountAssign() = default;
-  CountAssign& operator=(CountAssign const&) { ++copied; return *this; }
-  CountAssign& operator=(CountAssign&&) { ++moved; return *this; }
-};
-int CountAssign::copied = 0;
-int CountAssign::moved = 0;
-
 int main()
 {
+#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     {
         typedef std::pair<std::unique_ptr<int>, short> P;
         P p1(std::unique_ptr<int>(new int(3)), 4);
@@ -56,41 +28,5 @@ int main()
         assert(*p2.first == 3);
         assert(p2.second == 4);
     }
-    {
-        using P = std::pair<int&, int&&>;
-        int x = 42;
-        int y = 101;
-        int x2 = -1;
-        int y2 = 300;
-        P p1(x, std::move(y));
-        P p2(x2, std::move(y2));
-        p1 = std::move(p2);
-        assert(p1.first == x2);
-        assert(p1.second == y2);
-    }
-    {
-        using P = std::pair<int, NonAssignable>;
-        static_assert(!std::is_move_assignable<P>::value, "");
-    }
-    {
-        // The move decays to the copy constructor
-        CountAssign::reset();
-        using P = std::pair<CountAssign, CopyAssignable>;
-        static_assert(std::is_move_assignable<P>::value, "");
-        P p;
-        P p2;
-        p = std::move(p2);
-        assert(CountAssign::moved == 0);
-        assert(CountAssign::copied == 1);
-    }
-    {
-        CountAssign::reset();
-        using P = std::pair<CountAssign, MoveAssignable>;
-        static_assert(std::is_move_assignable<P>::value, "");
-        P p;
-        P p2;
-        p = std::move(p2);
-        assert(CountAssign::moved == 1);
-        assert(CountAssign::copied == 0);
-    }
+#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
 }