parse.y: "nil" for defined? with empty expression

* parse.y (new_defined): remove all extra parentheses, and return
  "nil" for defined? with empty expression.
  [ruby-core:54024] [Bug #8224]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40138 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 0 deletions

diff --git a/test/ruby/test_defined.rb b/test/ruby/test_defined.rb
index fe985340c1..511444fa8d 100644
--- a/test/ruby/test_defined.rb
+++ b/test/ruby/test_defined.rb
@@ -89,6 +89,13 @@ class TestDefined < Test::Unit::TestCase
     assert_equal("true", defined?(true))
     assert_equal("false", defined?(false))
     assert_equal("expression", defined?(1))
+
+    bug8224 = '[ruby-core:54024] [Bug #8224]'
+    (1..3).each do |level|
+      expr = "("*level+")"*level
+      assert_equal("nil", eval("defined? #{expr}"), "#{bug8224} defined? #{expr}")
+      assert_equal("nil", eval("defined?(#{expr})"), "#{bug8224} defined?(#{expr})")
+    end
   end
 
   def test_defined_impl_specific