PR c++/71568 - SFINAE forming pointer to member function

	* init.c (build_offset_ref): Check the return value of
	perform_or_defer_access_check.

From-SVN: r245763

gcc/cp/ChangeLog

+2017-02-27  Jason Merrill  <jason@redhat.com>
+
+	PR c++/71568 - SFINAE forming pointer to member function
+	* init.c (build_offset_ref): Check the return value of
+	perform_or_defer_access_check.
+
 2017-02-27  Marek Polacek  <polacek@redhat.com>
 
 	* decl.c (expand_static_init): Add missing } in a comment.

gcc/cp/init.c

@@ -2043,14 +2043,16 @@ build_offset_ref (tree type, tree member, bool address_p,
 	       If the access is to form a pointer to member, the
 	       nested-name-specifier shall name the derived class
 	       (or any class derived from that class).  */
+	  bool ok;
 	  if (address_p && DECL_P (t)
 	      && DECL_NONSTATIC_MEMBER_P (t))
-	    perform_or_defer_access_check (TYPE_BINFO (type), t, t,
+	    ok = perform_or_defer_access_check (TYPE_BINFO (type), t, t,
 						complain);
 	  else
-	    perform_or_defer_access_check (basebinfo, t, t,
+	    ok = perform_or_defer_access_check (basebinfo, t, t,
 						complain);
-
+	  if (!ok)
+	    return error_mark_node;
 	  if (DECL_STATIC_FUNCTION_P (t))
 	    return t;
 	  member = t;
@@ -2059,11 +2061,14 @@ build_offset_ref (tree type, tree member, bool address_p,
 	TREE_TYPE (member) = unknown_type_node;
     }
   else if (address_p && TREE_CODE (member) == FIELD_DECL)
+    {
       /* We need additional test besides the one in
 	 check_accessibility_of_qualified_id in case it is
 	 a pointer to non-static member.  */
-    perform_or_defer_access_check (TYPE_BINFO (type), member, member,
-				   complain);
+      if (!perform_or_defer_access_check (TYPE_BINFO (type), member, member,
+					  complain))
+	return error_mark_node;
+    }
 
   if (!address_p)
     {

gcc/testsuite/g++.dg/cpp0x/sfinae58.C

+// PR c++/71568
+// { dg-do compile { target c++11 } }
+
+template <typename T> class F : T {};
+template <typename> using void_t = void;
+template <class, class = void> struct G;
+template <typename T> struct G<T, void_t<decltype(&T::nlog_custom)>> {};
+struct D {
+  void nlog_custom();
+};
+G<F<D>> g;			// { dg-error "incomplete" }
+