From e7606de949fdae93ae51feed80a128511d66a9d3 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 22 Aug 2017 13:21:18 +0000
Subject: [PATCH] parse.y: primary should not be 0

* parse.y (primary): should not be 0, since it can be a receiver.
  [ruby-core:82447] [Bug #13836]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59644 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 parse.y                   | 2 +-
 test/ruby/test_defined.rb | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/parse.y b/parse.y
index 26763e9a00..14b5e9e3e9 100644
--- a/parse.y
+++ b/parse.y
@@ -2487,7 +2487,7 @@ primary		: literal
 		| tLPAREN_ARG {SET_LEX_STATE(EXPR_ENDARG);} rparen
 		    {
 		    /*%%%*/
-			$$ = 0;
+			$$ = NEW_BEGIN(0);
 		    /*%
 			$$ = dispatch1(paren, 0);
 		    %*/
diff --git a/test/ruby/test_defined.rb b/test/ruby/test_defined.rb
index de7ba9cc14..54f461ff03 100644
--- a/test/ruby/test_defined.rb
+++ b/test/ruby/test_defined.rb
@@ -99,6 +99,10 @@ class TestDefined < Test::Unit::TestCase
     end
   end
 
+  def test_defined_empty_paren_arg
+    assert_nil(defined?(p () + 1))
+  end
+
   def test_defined_impl_specific
     feature7035 = '[ruby-core:47558]' # not spec
     assert_predicate(defined?(Foo), :frozen?, feature7035)