Corrected const-correctness on nullptr type_traits, and beefed up the test for nullptr_t.

llvm-svn: 127338

libcxx/include/type_traits

@@ -211,6 +211,14 @@ template <>          struct __is_void<void> : public true_type {};
 template <class _Tp> struct _LIBCPP_VISIBLE is_void
     : public __is_void<typename remove_cv<_Tp>::type> {};
 
+// __is_nullptr_t
+
+template <class _Tp> struct ____is_nullptr_t       : public false_type {};
+template <>          struct ____is_nullptr_t<nullptr_t> : public true_type {};
+
+template <class _Tp> struct _LIBCPP_VISIBLE __is_nullptr_t
+    : public ____is_nullptr_t<typename remove_cv<_Tp>::type> {};
+
 // is_integral
 
 template <class _Tp> struct __is_integral                     : public false_type {};
@@ -392,18 +400,17 @@ template <class _Tp> struct _LIBCPP_VISIBLE is_arithmetic
 // is_fundamental
 
 template <class _Tp> struct _LIBCPP_VISIBLE is_fundamental
-    : public integral_constant<bool, is_void<_Tp>::value      ||
+    : public integral_constant<bool, is_void<_Tp>::value        ||
+                                     __is_nullptr_t<_Tp>::value ||
                                      is_arithmetic<_Tp>::value> {};
 
-template <> struct _LIBCPP_VISIBLE is_fundamental<nullptr_t>
-    : public true_type {};
-
 // is_scalar
 
 template <class _Tp> struct _LIBCPP_VISIBLE is_scalar
     : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
                                      is_member_pointer<_Tp>::value ||
                                      is_pointer<_Tp>::value        ||
+                                     __is_nullptr_t<_Tp>::value    ||
                                      is_enum<_Tp>::value           > {};
 
 template <> struct _LIBCPP_VISIBLE is_scalar<nullptr_t> : public true_type {};

libcxx/test/language.support/support.types/nullptr_t.pass.cpp

@@ -41,4 +41,19 @@ int main()
     assert(!(nullptr != nullptr));
     assert(!(nullptr < nullptr));
     assert(!(nullptr > nullptr));
+    A* a = nullptr;
+    assert(a == nullptr);
+    assert(a <= nullptr);
+    assert(a >= nullptr);
+    assert(!(a != nullptr));
+    assert(!(a < nullptr));
+    assert(!(a > nullptr));
+    assert(nullptr == a);
+    assert(nullptr <= a);
+    assert(nullptr >= a);
+    assert(!(nullptr != a));
+    assert(!(nullptr < a));
+    assert(!(nullptr > a));
+    std::ptrdiff_t i = reinterpret_cast<std::ptrdiff_t>(nullptr);
+    assert(i == 0);
 }