[PATCH] PR c++/42069

[Dodji Seketeli <dodji at redhat dot com>]

Hello,

In the example accompanying the patch below, we don't strip typedefs for
SCOPE_REFs nodes that are used as template arguments.

This causes a problem very similar to
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39754 .
The resolution of that PR did deal with stripping typedefs from /types/
used as template arguments. I didn't think about stripping typedefs from
SCOPE_REFs then.

The patch below plugs that hole.

Tested against trunk on x86_64-unknown-linux-gnu.

        Dodji

commit 4d40b664ded898c391369bf1401d6c4c4ff475db
Author: Dodji Seketeli <dodji@redhat.com>
Date:   Sun Nov 29 23:56:33 2009 +0100

    Fix PR c++/42069
    
    gcc/cp/ChangeLog:
    	PR c++/42069
    	* pt.c (convert_template_argument): Strip typedefs from SCOPE_REFs.
    
    gcc/testsuite/ChanageLog:
    	PR c++/42069
    	* g++.dg/template/typedef23.C: New test.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index eb1cdd3..62e931c 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -5526,6 +5526,13 @@ convert_template_argument (tree parm,
       if (TYPE_P (val))
 	val = strip_typedefs (val);
     }
+  else if (TREE_CODE (orig_arg) == SCOPE_REF)
+    {
+      /* Strip typedefs from the SCOPE_REF.  */
+      tree type = strip_typedefs (TREE_TYPE (orig_arg));
+      tree scope = strip_typedefs (TREE_OPERAND (orig_arg, 0));
+      val = build2 (SCOPE_REF, type, scope, TREE_OPERAND (orig_arg, 1));
+    }
   else
     {
       tree t = tsubst (TREE_TYPE (parm), args, complain, in_decl);
diff --git a/gcc/testsuite/g++.dg/template/typedef23.C b/gcc/testsuite/g++.dg/template/typedef23.C
new file mode 100644
index 0000000..e703550
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/typedef23.C
@@ -0,0 +1,25 @@
+// Contributed by Dodji Seketeli <dodji@redhat.com>
+// Origin PR c++/42069
+// { dg-do compile }
+
+struct A
+{
+  static const int N = 0;
+};
+
+template<int> struct B {};
+
+template<typename T, int>
+struct C
+{
+  typedef T U;
+  B<U::N> b;
+};
+
+template<typename T>
+struct C<T*, 0>
+{
+  B<T::N> b;
+};
+
+C<A*, 0> c;