Implement LWG2784, and mark 2786, 2795, 2804, 2812, 2826, 2834, 2837 and 2838 as complete - since we do them already

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@297752 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 51 insertions, 16 deletions

diff --git a/include/exception b/include/exception
index 8828709f8..216ae0c70 100644
--- a/include/exception
+++ b/include/exception
@@ -248,12 +248,17 @@ throw_with_nested (_Tp& __t, typename enable_if<
 #endif
 }
 
+template <class _From, class _To>
+struct __can_dynamic_cast : public _LIBCPP_BOOL_CONSTANT(
+              is_polymorphic<_From>::value &&
+                 (!is_base_of<_To, _From>::value ||
+                   is_convertible<const _From*, const _To*>::value)) {};
+
 template <class _Ep>
 inline _LIBCPP_INLINE_VISIBILITY
 void
-rethrow_if_nested(const _Ep& __e, typename enable_if<
-                                   is_polymorphic<_Ep>::value
-                                                   >::type* = 0)
+rethrow_if_nested(const _Ep& __e,
+                  typename enable_if< __can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
 {
     const nested_exception* __nep = dynamic_cast<const nested_exception*>(_VSTD::addressof(__e));
     if (__nep)
@@ -263,9 +268,8 @@ rethrow_if_nested(const _Ep& __e, typename enable_if<
 template <class _Ep>
 inline _LIBCPP_INLINE_VISIBILITY
 void
-rethrow_if_nested(const _Ep&, typename enable_if<
-                                   !is_polymorphic<_Ep>::value
-                                                   >::type* = 0)
+rethrow_if_nested(const _Ep&,
+                  typename enable_if<!__can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
 {
 }
 
diff --git a/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp b/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp
index 57d193a41..68cd85038 100644
--- a/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp
+++ b/test/std/language.support/support.exception/except.nested/rethrow_if_nested.pass.cpp
@@ -46,12 +46,19 @@ public:
 	C * operator&() const { assert(false); } // should not be called
 };
 
+class D : private std::nested_exception {};
+
+
+class E1 : public std::nested_exception {};
+class E2 : public std::nested_exception {};
+class E : public E1, public E2 {};
+
 int main()
 {
     {
         try
         {
-            A a(3);
+            A a(3);  // not a polymorphic type --> no effect
             std::rethrow_if_nested(a);
             assert(true);
         }
@@ -63,6 +70,30 @@ int main()
     {
         try
         {
+            D s;  // inaccessible base class --> no effect
+            std::rethrow_if_nested(s);
+            assert(true);
+        }
+        catch (...)
+        {
+            assert(false);
+        }
+    }
+    {
+        try
+        {
+            E s;  // ambiguous base class --> no effect
+            std::rethrow_if_nested(s);
+            assert(true);
+        }
+        catch (...)
+        {
+            assert(false);
+        }
+    }
+    {
+        try
+        {
             throw B(5);
         }
         catch (const B& b)
diff --git a/www/cxx1z_status.html b/www/cxx1z_status.html
index b31cdc6de..b37043e03 100644
--- a/www/cxx1z_status.html
+++ b/www/cxx1z_status.html
@@ -436,28 +436,28 @@
 	<tr><td><a href="http://wg21.link/LWG2769">2769</a></td><td>Redundant const in the return type of any_cast(const any&amp;)</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2781">2781</a></td><td>Contradictory requirements for std::function and std::reference_wrapper</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2782">2782</a></td><td>scoped_allocator_adaptor constructors must be constrained</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2784">2784</a></td><td>Resolution to LWG 2484 is missing "otherwise, no effects" and is hard to parse</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2784">2784</a></td><td>Resolution to LWG 2484 is missing "otherwise, no effects" and is hard to parse</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2785">2785</a></td><td>quoted should work with basic_string_view</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2786">2786</a></td><td>Annex C should mention shared_ptr changes for array support</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2786">2786</a></td><td>Annex C should mention shared_ptr changes for array support</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2787">2787</a></td><td>&sect;[file_status.cons] doesn't match class definition</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2788">2788</a></td><td>basic_string range mutators unintentionally require a default constructible allocator</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="http://wg21.link/LWG2789">2789</a></td><td>Equivalence of contained objects</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2790">2790</a></td><td>Missing specification of istreambuf_iterator::operator-&gt;</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="http://wg21.link/LWG2794">2794</a></td><td>Missing requirements for allocator pointers</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2795">2795</a></td><td>&sect;[global.functions] provides incorrect example of ADL use</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2795">2795</a></td><td>&sect;[global.functions] provides incorrect example of ADL use</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2796">2796</a></td><td>tuple should be a literal type</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="http://wg21.link/LWG2801">2801</a></td><td>Default-constructibility of unique_ptr</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="http://wg21.link/LWG2802">2802</a></td><td>shared_ptr constructor requirements for a deleter</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2804">2804</a></td><td>Unconditional constexpr default constructor for istream_iterator</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2804">2804</a></td><td>Unconditional constexpr default constructor for istream_iterator</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2806">2806</a></td><td>Base class of bad_optional_access</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2807">2807</a></td><td>std::invoke should use std::is_nothrow_callable</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2812">2812</a></td><td>Range access is available with &lt;string_view&gt;</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2812">2812</a></td><td>Range access is available with &lt;string_view&gt;</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2824">2824</a></td><td>list::sort should say that the order of elements is unspecified if an exception is thrown</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2826">2826</a></td><td>string_view iterators use old wording</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2834">2834</a></td><td>Resolution LWG 2223 is missing wording about end iterators</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2826">2826</a></td><td>string_view iterators use old wording</td><td>Kona</td><td>Complete</td></tr>
+	<tr><td><a href="http://wg21.link/LWG2834">2834</a></td><td>Resolution LWG 2223 is missing wording about end iterators</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2835">2835</a></td><td>LWG 2536 seems to misspecify &lt;tgmath.h&gt;</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2837">2837</a></td><td>gcd and lcm should support a wider range of input values</td><td>Kona</td><td></td></tr>
-	<tr><td><a href="http://wg21.link/LWG2838">2838</a></td><td>is_literal_type specification needs a little cleanup</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="http://wg21.link/LWG2837">2837</a></td><td>gcd and lcm should support a wider range of input values</td><td>Kona</td><td>Complete</td></tr>
+	<tr><td><a href="http://wg21.link/LWG2838">2838</a></td><td>is_literal_type specification needs a little cleanup</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="http://wg21.link/LWG2842">2842</a></td><td>in_place_t check for optional::optional(U&amp;&amp;) should decay U</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="http://wg21.link/LWG2850">2850</a></td><td>std::function move constructor does unnecessary work</td><td>Kona</td><td></td></tr>
 	<tr><td><a href="http://wg21.link/LWG2853">2853</a></td><td>Possible inconsistency in specification of erase in [vector.modifiers]</td><td>Kona</td><td></td></tr>