lib/parser/ruby23.y in parser-2.3.1.2 vs lib/parser/ruby23.y in parser-2.3.1.3

@@ -1362,9 +1362,12 @@
                       result = val[0].
                                   concat(val[2]).
                                   concat(val[3])
                     }
                 | f_arg tCOMMA
+                  {
+                    result = [@builder.multi_lhs(nil, val[0], nil)]
+                  }
                 | f_arg tCOMMA                       f_rest_arg tCOMMA f_arg opt_block_args_tail
                     {
                       result = val[0].
                                   concat(val[2]).
                                   concat(val[4]).