[C++ PATCH] Fix dynamic_cast<XXX &> in template (PR c++/34364)

[Jakub Jelinek]

Hi!

The following valid testcase is rejected, because unlike
build_static_cast/build_const_cast/build_reinterpret_cast
build_dynamic_cast doesn't convert_from_reference when
processing_template_decl, so a REFERENCE_TYPE object leaks all the
way through into finish_class_member_access_expr, where it is rejected
as non-class type.  When not processing_template_decl,
convert_from_reference is called even in build_dynamic_cast.

Regtested on x86_64-linux, ok for trunk?

2007-12-10  Jakub Jelinek  <jakub@redhat.com>

	PR c++/34364
	* rtti.c (build_dynamic_cast): Call convert_from_reference even for
	dynamic_cast in a template.

	* g++.dg/rtti/dyncast2.C: New test.

--- gcc/cp/rtti.c.jj	2007-11-01 20:59:36.000000000 +0100
+++ gcc/cp/rtti.c	2007-12-10 23:18:58.000000000 +0100
@@ -728,8 +728,7 @@ build_dynamic_cast (tree type, tree expr
     {
       expr = build_min (DYNAMIC_CAST_EXPR, type, expr);
       TREE_SIDE_EFFECTS (expr) = 1;
-
-      return expr;
+      return convert_from_reference (expr);
     }
 
   return convert_from_reference (build_dynamic_cast_1 (type, expr));
--- gcc/testsuite/g++.dg/rtti/dyncast2.C.jj	2007-12-10 23:21:13.000000000 +0100
+++ gcc/testsuite/g++.dg/rtti/dyncast2.C	2007-12-10 23:20:09.000000000 +0100
@@ -0,0 +1,31 @@
+// PR c++/34364
+// { dg-do run }
+
+struct A
+{
+  virtual ~A () {}
+};
+
+struct B : public A
+{
+  template <typename T> struct C
+  {
+    static void f (A &a)
+    {
+      dynamic_cast <B &>(a).g ();
+    }
+  };
+
+  B () : c (6) {}
+  void g () { c++; }
+  int c;
+};
+
+B b;
+
+int
+main (void)
+{
+  B::C<int>::f (b);
+  return b.c != 7;
+}

	Jakub