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

3 files changed, 30 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index c5fe871ada..f0dba22e9c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Apr  6 02:30:28 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (new_defined): remove all extra parentheses, and return
+	  "nil" for defined? with empty expression.
+	  [ruby-core:54024] [Bug #8224]
+
 Sat Apr  6 02:06:04 2013  Aaron Patterson <aaron@tenderlovemaking.com>
 
 	* ext/psych/lib/psych/visitors/to_ruby.rb: correctly register
diff --git a/parse.y b/parse.y
index 0f0fbe8346..d6645c5f4f 100644
--- a/parse.y
+++ b/parse.y
@@ -369,6 +369,7 @@ static void fixpos(NODE*,NODE*);
 static int value_expr_gen(struct parser_params*,NODE*);
 static void void_expr_gen(struct parser_params*,NODE*);
 static NODE *remove_begin(NODE*);
+static NODE *remove_begin_all(NODE*);
 #define value_expr(node) value_expr_gen(parser, (node) = remove_begin(node))
 #define void_expr0(node) void_expr_gen(parser, (node))
 #define void_expr(node) void_expr0((node) = remove_begin(node))
@@ -438,6 +439,8 @@ static NODE *new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs, ID
 static NODE *new_const_op_assign_gen(struct parser_params *parser, NODE *lhs, ID op, NODE *rhs);
 #define new_const_op_assign(lhs, op, rhs) new_const_op_assign_gen(parser, (lhs), (op), (rhs))
 
+#define new_defined(expr) NEW_DEFINED(remove_begin_all(expr))
+
 static NODE *match_op_gen(struct parser_params*,NODE*,NODE*);
 #define match_op(node1,node2) match_op_gen(parser, (node1), (node2))
 
@@ -616,6 +619,8 @@ new_args_tail_gen(struct parser_params *parser, VALUE k, VALUE kr, VALUE b)
 }
 #define new_args_tail(k,kr,b) new_args_tail_gen(parser, (k),(kr),(b))
 
+#define new_defined(expr) dispatch1(defined, (expr))
+
 #define FIXME 0
 
 #endif /* RIPPER */
@@ -2305,7 +2310,7 @@ arg		: lhs '=' arg
 		    {
 		    /*%%%*/
 			in_defined = 0;
-			$$ = NEW_DEFINED($4);
+			$$ = new_defined($4);
 		    /*%
 			in_defined = 0;
 			$$ = dispatch1(defined, $4);
@@ -2705,7 +2710,7 @@ primary		: literal
 		    {
 		    /*%%%*/
 			in_defined = 0;
-			$$ = NEW_DEFINED($5);
+			$$ = new_defined($5);
 		    /*%
 			in_defined = 0;
 			$$ = dispatch1(defined, $5);
@@ -8926,6 +8931,16 @@ remove_begin(NODE *node)
     return node;
 }
 
+static NODE *
+remove_begin_all(NODE *node)
+{
+    NODE **n = &node, *n1 = node;
+    while (n1 && nd_type(n1) == NODE_BEGIN) {
+	*n = n1 = n1->nd_body;
+    }
+    return node;
+}
+
 static void
 reduce_nodes_gen(struct parser_params *parser, NODE **body)
 {
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