Made a stab at has_copy_constructor. Got it mostly working for g++-4.0, but only works for scalar types on clang. Ultimately this needs a compiler-supported is_constructible which clang is missing, and won't be able to use until it gets variadic templates.

llvm-svn: 113304

3 files changed, 71 insertions, 9 deletions

diff --git a/libcxx/include/type_traits b/libcxx/include/type_traits
index 9ae3d6f6ab9..0f45f489dab 100644
--- a/libcxx/include/type_traits
+++ b/libcxx/include/type_traits
@@ -761,10 +761,6 @@ template <class _Tp> struct has_nothrow_copy_constructor
 
 template <class _Tp> struct has_nothrow_move_constructor : public has_nothrow_copy_constructor<_Tp> {};
 
-// has_copy_constructor
-
-template <class _Tp> struct has_copy_constructor : public true_type {};
-
 // has_copy_assign
 
 template <class _Tp> struct has_copy_assign;
@@ -1732,6 +1728,24 @@ struct __is_constructible0_imp<false, _A[]>
 
 #endif  // _LIBCPP_HAS_NO_ADVANCED_SFINAE
 
+// has_copy_constructor
+
+#ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
+
+template <class _Tp>
+struct has_copy_constructor
+    : public is_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
+    {};
+
+#else  // _LIBCPP_HAS_NO_ADVANCED_SFINAE
+
+template <class _Tp>
+struct has_copy_constructor
+    : public has_nothrow_copy_constructor<_Tp>
+    {};
+
+#endif  // _LIBCPP_HAS_NO_ADVANCED_SFINAE
+
 template <class _Tp> struct __is_zero_default_constructible
     : public integral_constant<bool, is_scalar<_Tp>::value || is_empty<_Tp>::value> {};
 
diff --git a/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_copy_constructor.pass.cpp b/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_copy_constructor.pass.cpp
index 7acb69509fe..f3364c1cf1f 100644
--- a/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_copy_constructor.pass.cpp
+++ b/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_copy_constructor.pass.cpp
@@ -13,7 +13,55 @@
 
 #include <type_traits>
 
+template <class T, bool Result>
+void test_has_copy_constructor()
+{
+    static_assert(std::has_copy_constructor<T>::value == Result, "");
+}
+
+class Empty
+{
+};
+
+class NotEmpty
+{
+public:
+    virtual ~NotEmpty();
+};
+
+union Union {};
+
+struct bit_zero
+{
+    int :  0;
+};
+
+class Abstract
+{
+public:
+    virtual ~Abstract() = 0;
+};
+
+struct A
+{
+    A(const A&);
+};
+
 int main()
 {
-#error has_copy_constructor not implemented
+    test_has_copy_constructor<char[3], false>();
+    test_has_copy_constructor<char[], false>();
+    test_has_copy_constructor<void, false>();
+    test_has_copy_constructor<Abstract, false>();
+
+    test_has_copy_constructor<A, true>();
+    test_has_copy_constructor<int&, true>();
+    test_has_copy_constructor<Union, true>();
+    test_has_copy_constructor<Empty, true>();
+    test_has_copy_constructor<int, true>();
+    test_has_copy_constructor<double, true>();
+    test_has_copy_constructor<int*, true>();
+    test_has_copy_constructor<const int*, true>();
+    test_has_copy_constructor<NotEmpty, true>();
+    test_has_copy_constructor<bit_zero, true>();
 }
diff --git a/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_nothrow_copy_constructor.pass.cpp b/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_nothrow_copy_constructor.pass.cpp
index f2ebadd4e12..8dbd3e8eebf 100644
--- a/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_nothrow_copy_constructor.pass.cpp
+++ b/libcxx/test/utilities/meta/meta.unary/meta.unary.prop/has_nothrow_copy_constructor.pass.cpp
@@ -61,11 +61,11 @@ struct A
 
 int main()
 {
-//    test_has_not_nothrow_copy_constructor<void>();
+    test_has_not_nothrow_copy_constructor<void>();
     test_has_not_nothrow_copy_constructor<A>();
     test_has_not_nothrow_copy_constructor<Abstract>();
-//    test_has_not_nothrow_copy_constructor<char[3]>();
-//    test_has_not_nothrow_copy_constructor<char[]>();
+    test_has_not_nothrow_copy_constructor<char[3]>();
+    test_has_not_nothrow_copy_constructor<char[]>();
 
     test_has_nothrow_copy_constructor<int&>();
     test_has_nothrow_copy_constructor<Union>();
@@ -74,6 +74,6 @@ int main()
     test_has_nothrow_copy_constructor<double>();
     test_has_nothrow_copy_constructor<int*>();
     test_has_nothrow_copy_constructor<const int*>();
-//    test_has_nothrow_copy_constructor<NotEmpty>();
+    test_has_nothrow_copy_constructor<NotEmpty>();
     test_has_nothrow_copy_constructor<bit_zero>();
 }