parse.y: fix block passing with empty kwargs

* parse.y (arg_blk_pass): preceeding arguments node may be NULL when
  an empty keyword argument hash splat is optimized away.
  [ruby-core:88890] [Bug #15087]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64786 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/parse.y b/parse.y
index fb471803a5..3763dabf3a 100644
--- a/parse.y
+++ b/parse.y
@@ -9962,6 +9962,7 @@ static NODE *
 arg_blk_pass(NODE *node1, NODE *node2)
 {
     if (node2) {
+        if (!node1) return node2;
 	node2->nd_head = node1;
 	nd_set_first_lineno(node2, nd_first_lineno(node1));
 	nd_set_first_column(node2, nd_first_column(node1));