- * The default merge_sets_func implementation. If n_old_nodes is equal 1, copies
- * the debug info from the old node to all new ones (if they do not have one), else does nothing.
- *
- * @param new_nodes An array of new Firm nodes.
- * @param n_new_nodes The length of the new_nodes array.
- * @param old_nodes An array of old (replaced) Firm nodes.
- * @param n_old_nodes The length of the old_nodes array.
- * @param info The action that cause old node to be replaced by new one.
+ * The type of the debug info retriever function.
+ * When given a dbg_info returns the name (usually the filename) of the
+ * compilation unit defining it. @p line is set to the line number of the
+ * definition.