[C++ PATCH] Partial ordering bug with template template parm

[Kriang Lerdsuwanakij <lerdsuwa at scf dot usc dot edu>]

Hi,

I discovered a bug when unifying two template template parameters
bound with arguments.  unify rejected all such cases.  This leads
to incorrect function template partial ordering.  A test case is
povided below.  There should be no ambiguity deciding g() in both
cases.  The attached patch corrects this.

--Kriang


ChangeLog:

2000-09-25  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>

	* pt.c (unify): Handle when both ARG and PARM are
	BOUND_TEMPLATE_TEMPLATE_PARM.


diff -cprN gcc-old/cp/pt.c gcc/cp/pt.c
*** gcc-old/cp/pt.c	Mon Sep 25 17:49:11 2000
--- gcc/cp/pt.c	Mon Sep 25 17:48:06 2000
*************** unify (tparms, targs, parm, arg, strict)
*** 8323,8338 ****
  
        if (TREE_CODE (parm) == BOUND_TEMPLATE_TEMPLATE_PARM)
  	{
! 	  /* ARG must be constructed from a template class.  */
! 	  if (TREE_CODE (arg) != RECORD_TYPE || !CLASSTYPE_TEMPLATE_INFO (arg))
  	    return 1;
  
  	  {
  	    tree parmtmpl = TYPE_TI_TEMPLATE (parm);
  	    tree parmvec = TYPE_TI_ARGS (parm);
! 	    tree argvec = CLASSTYPE_TI_ARGS (arg);
  	    tree argtmplvec
! 	      = DECL_INNERMOST_TEMPLATE_PARMS (CLASSTYPE_TI_TEMPLATE (arg));
  	    int i;
  
  	    /* The parameter and argument roles have to be switched here 
--- 8323,8340 ----
  
        if (TREE_CODE (parm) == BOUND_TEMPLATE_TEMPLATE_PARM)
  	{
! 	  /* ARG must be constructed from a template class or a template
! 	     template parameter.  */
! 	  if (TREE_CODE (arg) != BOUND_TEMPLATE_TEMPLATE_PARM
! 	      && (TREE_CODE (arg) != RECORD_TYPE || !CLASSTYPE_TEMPLATE_INFO (arg)))
  	    return 1;
  
  	  {
  	    tree parmtmpl = TYPE_TI_TEMPLATE (parm);
  	    tree parmvec = TYPE_TI_ARGS (parm);
! 	    tree argvec = TYPE_TI_ARGS (arg);
  	    tree argtmplvec
! 	      = DECL_INNERMOST_TEMPLATE_PARMS (TYPE_TI_TEMPLATE (arg));
  	    int i;
  
  	    /* The parameter and argument roles have to be switched here 
*************** unify (tparms, targs, parm, arg, strict)
*** 8361,8367 ****
  		  return 1;
  	      }
  	  }
! 	  arg = CLASSTYPE_TI_TEMPLATE (arg);
  
  	  /* Fall through to deduce template name.  */
  	}
--- 8363,8369 ----
  		  return 1;
  	      }
  	  }
! 	  arg = TYPE_TI_TEMPLATE (arg);
  
  	  /* Fall through to deduce template name.  */
  	}
diff -cprN gcc-old/testsuite/g++.old-deja/g++.pt/ttp65.C gcc/testsuite/g++.old-deja/g++.pt/ttp65.C
*** gcc-old/testsuite/g++.old-deja/g++.pt/ttp65.C	Wed Dec 31 16:00:00 1969
--- gcc/testsuite/g++.old-deja/g++.pt/ttp65.C	Mon Sep 25 17:48:28 2000
***************
*** 0 ****
--- 1,38 ----
+ // Build don't link:
+ 
+ // Copyright (C) 2000 Free Software Foundation
+ // Contributed by Kriang Lerdsuwanakij <lerdsuwa@users.sourceforge.net>
+ 
+ // Bug: We used reject template unification of two bound template template
+ // parameters.
+ 
+ template <class T, class U=int> class C
+ {
+ };
+ 
+ template <class T, class U> void f(C<T,U> c)
+ {
+ }
+ 
+ template <class T> void f(C<T> c)
+ {
+ }
+ 
+ template <template<class,class=int> class C, class T, class U>
+ void g(C<T,U> c)
+ {
+ }
+ 
+ template <template<class,class=int> class C, class T> void g(C<T> c)
+ {
+ }
+ 
+ int main()
+ {
+   C<int,char> c1;
+   f(c1);
+   g(c1);
+   C<int,int> c2;
+   f(c2);
+   g(c2);
+ }