re PR c++/7919 (using declarations screw this pointer)

cp:
	PR c++/7919
	* call.c (build_over_call): Convert this pointer for fns found by
	using decls.
testsuite:
	* g++.dg/inherit/using2.C: New test.

From-SVN: r57165

gcc/cp/ChangeLog

+2002-09-15  Nathan Sidwell  <nathan@codesourcery.com>
+
+	PR c++/7919
+	* call.c (build_over_call): Convert this pointer for fns found by
+	using decls.
+
 2002-09-15  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* ChangeLog: Follow spelling conventions.

gcc/cp/call.c

@@ -4336,7 +4336,8 @@ build_over_call (cand, args, flags)
       tree parmtype = TREE_VALUE (parm);
       tree argtype = TREE_TYPE (TREE_VALUE (arg));
       tree converted_arg;
-
+      tree base_binfo;
+      
       if (ICS_BAD_FLAG (TREE_VEC_ELT (convs, i)))
 	pedwarn ("passing `%T' as `this' argument of `%#D' discards qualifiers",
 		    TREE_TYPE (argtype), fn);
@@ -4354,6 +4355,15 @@ build_over_call (cand, args, flags)
 				       TREE_VALUE (arg),
 				       cand->conversion_path,
 				       1);
+      /* If fn was found by a using declaration, the conversion path
+         will be to the derived class, not the base declaring fn. We
+         must convert from derived to base.  */
+      base_binfo = lookup_base (TREE_TYPE (TREE_TYPE (converted_arg)),
+				TREE_TYPE (parmtype), ba_ignore, NULL);
+      
+      converted_arg = build_base_path (PLUS_EXPR, converted_arg,
+				       base_binfo, 1);
+      
       converted_args = tree_cons (NULL_TREE, converted_arg, converted_args);
       parm = TREE_CHAIN (parm);
       arg = TREE_CHAIN (arg);

gcc/testsuite/ChangeLog

+2002-09-15  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* g++.dg/inherit/using2.C: New test.
+
 2002-09-15  Kazu Hirata  <kazu@cs.umass.edu>
 
 	* ChangeLog: Follow spelling conventions.

gcc/testsuite/g++.dg/inherit/using2.C

+// { dg-do run }
+
+// Copyright (C) 2002 Free Software Foundation, Inc.
+// Contributed by Nathan Sidwell 15 Sep 2002 <nathan@codesourcery.com>
+
+// PR 7919. Methods found via using decls didn't have their this
+// pointers converted to the final base type.
+
+struct Base {
+  int m;
+  protected:
+  void *Return () { return this; }
+};
+
+struct Derived : Base {
+  using Base::Return;
+  virtual ~Derived () {}
+};
+
+int main ()
+{
+  Derived d;
+  
+  return static_cast <Base *> (&d) != d.Return ();
+}