parse.y (arg_append): support NODE_ARGSCAT case

Because of the lack of this case, `[*ary,1,2,3,4,5,6]` was parsed into
an inefficient AST like `ary + [1,2] + [3,4] + [5,6]`.

A patch from Anmol Chopra <anmolchopra@rocketbox.in>.
Fixes [Bug #15018].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64510 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 5 insertions, 0 deletions

diff --git a/parse.y b/parse.y
index 9971ba0551..fb471803a5 100644
--- a/parse.y
+++ b/parse.y
@@ -9301,6 +9301,11 @@ arg_append(struct parser_params *p, NODE *node1, NODE *node2, const YYLTYPE *loc
 	node1->nd_loc.end_pos = node1->nd_body->nd_loc.end_pos;
 	nd_set_type(node1, NODE_ARGSCAT);
 	return node1;
+      case NODE_ARGSCAT:
+        if (nd_type(node1->nd_body) != NODE_ARRAY) break;
+        node1->nd_body = list_append(p, node1->nd_body, node2);
+        node1->nd_loc.end_pos = node1->nd_body->nd_loc.end_pos;
+        return node1;
     }
     return NEW_ARGSPUSH(node1, node2, loc);
 }