re PR c++/23840 (Bogus "invalid lvalue in unary '&'" diagnostic and ICE with va_arg)

	PR c++/23840
	* tree.c (lvalue_p1): A VA_ARG_EXPR with class type is an lvalue,
	when class rvalues are lvalues.

	PR c++/23840
	* g++.dg/expr/stdarg1.C: New test.

From-SVN: r104877

gcc/cp/ChangeLog

+2005-10-02  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23840
+	* tree.c (lvalue_p1): A VA_ARG_EXPR with class type is an lvalue,
+	when class rvalues are lvalues.
+
 2005-09-28  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/16782

gcc/cp/tree.c

@@ -158,8 +158,12 @@ lvalue_p_1 (tree ref,
     case TARGET_EXPR:
       return treat_class_rvalues_as_lvalues ? clk_class : clk_none;
 
-    case CALL_EXPR:
     case VA_ARG_EXPR:
+      return (treat_class_rvalues_as_lvalues
+	      && CLASS_TYPE_P (TREE_TYPE (ref))
+	      ? clk_class : clk_none);
+
+    case CALL_EXPR:
       /* Any class-valued call would be wrapped in a TARGET_EXPR.  */
       return clk_none;
 

gcc/testsuite/ChangeLog

+2005-10-02  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/23840
+	* g++.dg/expr/stdarg1.C: New test.
+
 2005-10-02  Diego Novillo  <dnovillo@redhat.com>
 
 	PR 24142

gcc/testsuite/g++.dg/expr/stdarg1.C

+// PR c++/23840
+
+#include <stdarg.h>
+struct S 
+{
+  int f(int);
+};
+void f(int i, ...) 
+{
+  va_list ap;
+  va_start (ap, i);
+  va_arg (ap, S).f(0);
+}