[C++] Weffc++/Wnon-virtual-dtor confusion

Index: cp/class.c
===================================================================
--- cp/class.c	(revision 209122)
+++ cp/class.c	(working copy)
@@ -5570,21 +5570,24 @@  check_bases_and_members (tree t)
   TYPE_HAS_COMPLEX_MOVE_ASSIGN (t) |= TYPE_CONTAINS_VPTR_P (t);
   TYPE_HAS_COMPLEX_DFLT (t) |= TYPE_CONTAINS_VPTR_P (t);
 
-  /* Warn if a base of a polymorphic type has an accessible
+  /* Warn if a public base of a polymorphic type has an accessible
      non-virtual destructor.  It is only now that we know the class is
      polymorphic.  Although a polymorphic base will have a already
      been diagnosed during its definition, we warn on use too.  */
   if (TYPE_POLYMORPHIC_P (t) && warn_nonvdtor)
     {
-      tree binfo, base_binfo;
+      tree binfo = TYPE_BINFO (t);
+      vec<tree, va_gc> *accesses = BINFO_BASE_ACCESSES (binfo);
+      tree base_binfo;
       unsigned i;
       
-      for (binfo = TYPE_BINFO (t), i = 0;
-	   BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
+      for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
 	{
 	  tree basetype = TREE_TYPE (base_binfo);
 
-	  if (accessible_nvdtor_p (basetype))
+	  if ((*accesses)[i] == access_public_node
+	      && (TYPE_POLYMORPHIC_P (basetype) || warn_ecpp)
+	      && accessible_nvdtor_p (basetype))
 	    warning (OPT_Wnon_virtual_dtor,
 		     "base class %q#T has accessible non-virtual destructor",
 		     basetype);
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi	(revision 209122)
+++ doc/invoke.texi	(working copy)
@@ -2670,10 +2670,10 @@  the compiler to never throw an exception
 @opindex Wnon-virtual-dtor
 @opindex Wno-non-virtual-dtor
 Warn when a class has virtual functions and an accessible non-virtual
-destructor itself or in a base class, or has in which case it is
-possible but unsafe to delete an instance of a derived class through a
-pointer to the base class.  This warning is automatically enabled if
-@option{-Weffc++} is specified.
+destructor itself or in an accessible polymorphic base class, in which
+case it is possible but unsafe to delete an instance of a derived
+class through a pointer to the class itself or base class.  This
+warning is automatically enabled if @option{-Weffc++} is specified.
 
 @item -Wreorder @r{(C++ and Objective-C++ only)}
 @opindex Wreorder
@@ -2743,7 +2743,9 @@  Never overload @code{&&}, @code{||}, or
 @end itemize
 
 This option also enables @option{-Wnon-virtual-dtor}, which is also
-one of the effective C++ recommendations.
+one of the effective C++ recommendations.  However, the check is
+extended to warn about the lack of virtual destructor in accessible
+non-polymorphic bases classes too.
 
 When selecting this option, be aware that the standard library
 headers do not obey all of these guidelines; use @samp{grep -v}
Index: testsuite/g++.dg/warn/Wnvdtor-2.C
===================================================================
--- testsuite/g++.dg/warn/Wnvdtor-2.C	(revision 209122)
+++ testsuite/g++.dg/warn/Wnvdtor-2.C	(working copy)
@@ -54,4 +54,23 @@  public:
 };
 
 struct H {};
-struct I : H {};
+
+struct I1 : H
+{};
+struct I2 : private H
+{};
+
+struct J1 : H
+{ virtual ~J1 ();};
+struct J2 : private H
+{ virtual ~J2 ();};
+
+struct K // { dg-warning "accessible non-virtual destructor" }
+{
+  virtual void k ();
+};
+
+struct L1 : K // { dg-warning "accessible non-virtual destructor" }
+{virtual ~L1 ();};
+struct L2 : private K
+{virtual ~L2 ();};
Index: testsuite/g++.dg/warn/Wnvdtor-3.C
===================================================================
--- testsuite/g++.dg/warn/Wnvdtor-3.C	(revision 209122)
+++ testsuite/g++.dg/warn/Wnvdtor-3.C	(working copy)
@@ -53,4 +53,23 @@  public:
 };
 
 struct H {};
-struct I : H {};
+
+struct I1 : H
+{};
+struct I2 : private H
+{};
+
+struct J1 : H // { dg-warning "accessible non-virtual destructor" }
+{ virtual ~J1 ();};
+struct J2 : private H
+{ virtual ~J2 ();};
+
+struct K // { dg-warning "accessible non-virtual destructor" }
+{
+  virtual void k ();
+};
+
+struct L1 : K // { dg-warning "accessible non-virtual destructor" }
+{virtual ~L1 ();};
+struct L2 : private K
+{virtual ~L2 ();};
Index: testsuite/g++.dg/warn/Wnvdtor-4.C
===================================================================
--- testsuite/g++.dg/warn/Wnvdtor-4.C	(revision 209122)
+++ testsuite/g++.dg/warn/Wnvdtor-4.C	(working copy)
@@ -53,4 +53,23 @@  public:
 };
 
 struct H {};
-struct I : H {};
+
+struct I1 : H
+{};
+struct I2 : private H
+{};
+
+struct J1 : H
+{ virtual ~J1 ();};
+struct J2 : private H
+{ virtual ~J2 ();};
+
+struct K 
+{
+  virtual void k ();
+};
+
+struct L1 : K
+{virtual ~L1 ();};
+struct L2 : private K
+{virtual ~L2 ();};