[C++ PATCH] Fix PR10552

[Kriang Lerdsuwanakij]

Hi

This patch fixes a latent bug during template template argument
substitution.  Normally, we don't have to process any TEMPLATE_DECL
that appears as template template argument.  However, we need to
deal with one special case, i.e., when it is an unqualified name
that is a member class template nested inside a template class.  
This is described in detail in the comment within the patch.  

Tested on i686-pc-linux-gnu.  OK to commit to main trunk?

--Kriang


2003-05-01  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>

	PR c++/10552
	* pt.c (tsubst_copy): Handle TEMPLATE_DECL that is a member class
	template and has dependent context.

2003-05-01  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>

	PR c++/10552
	* g++.dg/template/ttp6.C: New test.



diff -cprN gcc-main-save/gcc/cp/pt.c gcc-main-new/gcc/cp/pt.c
*** gcc-main-save/gcc/cp/pt.c	Tue Apr 29 21:11:06 2003
--- gcc-main-new/gcc/cp/pt.c	Thu May  1 20:22:13 2003
*************** tsubst_copy (t, args, complain, in_decl)
*** 7287,7293 ****
--- 7289,7317 ----
  		       args, complain, in_decl);
        else if (is_member_template (t))
  	return tsubst (t, args, complain, in_decl);
+       else if (DECL_CLASS_SCOPE_P (t)
+ 	       && uses_template_parms (DECL_CONTEXT (t)))
+ 	{
+ 	  /* Template template argument like the following example need
+ 	     special treatment:
+ 
+ 	       template <template <class> class TT> struct C {};
+ 	       template <class T> struct D {
+ 		 template <class U> struct E {};
+ 	 	 C<E> c;				// #1
+ 	       };
+ 	       D<int> d;				// #2
+ 
+ 	     We are processing the template argument `E' in #1 for
+ 	     the template instantiation #2.  Originally, `E' is a
+ 	     TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT.  Now we
+ 	     have to substitute this with one having context `D<int>'.  */
+ 
+ 	  tree context = tsubst (DECL_CONTEXT (t), args, complain, in_decl);
+ 	  return lookup_field (context, DECL_NAME(t), 0, false);
+ 	}
        else
+ 	/* Ordinary template template argument.  */
  	return t;
  
      case LOOKUP_EXPR:
diff -cprN gcc-main-save/gcc/testsuite/g++.dg/template/ttp6.C gcc-main-new/gcc/testsuite/g++.dg/template/ttp6.C
*** gcc-main-save/gcc/testsuite/g++.dg/template/ttp6.C	Thu Jan  1 07:00:00 1970
--- gcc-main-new/gcc/testsuite/g++.dg/template/ttp6.C	Thu May  1 20:28:46 2003
***************
*** 0 ****
--- 1,21 ----
+ // { dg-do compile }
+ 
+ // Origin: Eelis van der Weegan <gccbugs@contacts.eelis.net>
+ 
+ // PR c++/10552: Member class template as template template argument
+ // substitution issue.
+ 
+ template <template <typename> class A, typename>
+ struct B
+ {
+   typedef typename A<int>::t t;
+ };
+ 
+ template <typename D>
+ struct E
+ {
+   template <typename> struct F { typedef int t; };
+   typedef typename B<F, D>::t t;
+ };
+ 
+ typedef E<int>::t t;