re PR c++/37766 ([C++0x] ICE with function's default reference template parameter)

	PR c++/37766
	* pt.c (type_unification_real): Call convert_template_argument
	for function default template arguments.
	(check_default_tmpl_args): Suggest -std=c++0x when function default
	template args seen in C++98 mode.

From-SVN: r152685

gcc/cp/ChangeLog

+2009-10-12  Jason Merrill  <jason@redhat.com>
+
+	PR c++/37766
+	* pt.c (type_unification_real): Call convert_template_argument
+	for function default template arguments.
+	(check_default_tmpl_args): Suggest -std=c++0x when function default
+	template args seen in C++98 mode.
+
 2009-10-11  Jason Merrill  <jason@redhat.com>
 
 	PR c++/37204

gcc/cp/pt.c

@@ -4025,7 +4025,8 @@ check_default_tmpl_args (tree decl, tree parms, int is_primary,
   else if (is_friend_decl)
     msg = "default template arguments may not be used in function template friend declarations";
   else if (TREE_CODE (decl) == FUNCTION_DECL && (cxx_dialect == cxx98))
-    msg = "default template arguments may not be used in function templates";
+    msg = ("default template arguments may not be used in function templates "
+	   "without -std=c++0x or -std=gnu++0x");
   else if (is_partial)
     msg = "default template arguments may not be used in partial specializations";
   else
@@ -13178,9 +13179,11 @@ type_unification_real (tree tparms,
 	     to explicitly check cxx_dialect here.  */
           if (TREE_PURPOSE (TREE_VEC_ELT (tparms, i)))
             {
-              tree arg = tsubst_template_arg
-				(TREE_PURPOSE (TREE_VEC_ELT (tparms, i)),
-				 targs, tf_none, NULL_TREE);
+	      tree parm = TREE_VALUE (TREE_VEC_ELT (tparms, i));
+	      tree arg = TREE_PURPOSE (TREE_VEC_ELT (tparms, i));
+              arg = tsubst_template_arg (arg, targs, tf_none, NULL_TREE);
+	      arg = convert_template_argument (parm, arg, targs, tf_none,
+					       i, NULL_TREE);
               if (arg == error_mark_node)
                 return 1;
               else

gcc/testsuite/ChangeLog

+2009-10-12  Jason Merrill  <jason@redhat.com>
+
+	PR c++/37766
+	* g++.dg/cpp0x/fntmpdefarg1.C: New.
+
 2009-10-12  Janis Johnson  <janis187@us.ibm.com>
 
 	* gcc.dg/lto/20090914-2.c: Fix typos in test directives.

gcc/testsuite/g++.dg/cpp0x/fntmpdefarg1.C

+// PR c++/37766
+// { dg-options -std=c++0x }
+
+int a = 1;
+template<int& b = a> void f() {
+  f<>();
+}