+/* If the set of template parameters PARMS contains a template parameter
+ at the given LEVEL and INDEX, then return this parameter. Otherwise
+ return NULL_TREE. */
+
+static tree
+corresponding_template_parameter (tree parms, int level, int index)
+{
+ while (TMPL_PARMS_DEPTH (parms) > level)
+ parms = TREE_CHAIN (parms);
+
+ if (TMPL_PARMS_DEPTH (parms) != level
+ || TREE_VEC_LENGTH (TREE_VALUE (parms)) <= index)
+ return NULL_TREE;
+
+ tree t = TREE_VALUE (TREE_VEC_ELT (TREE_VALUE (parms), index));
+ /* As in template_parm_to_arg. */
+ if (TREE_CODE (t) == TYPE_DECL || TREE_CODE (t) == TEMPLATE_DECL)
+ t = TREE_TYPE (t);
+ else
+ t = DECL_INITIAL (t);
+
+ gcc_assert (TEMPLATE_PARM_P (t));
+ return t;
+}
+
+/* Return the template parameter from PARMS that positionally corresponds
+ to the template parameter PARM, or else return NULL_TREE. */
+
+static tree
+corresponding_template_parameter (tree parms, tree parm)
+{
+ int level, index;
+ template_parm_level_and_index (parm, &level, &index);
+ return corresponding_template_parameter (parms, level, index);
+}
+