diff --git a/ChangeLog b/ChangeLog
index ea44ddb900..0b2581d069 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Dec 12 12:44:39 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* parse.y (expr): 'not' and '!' should act as conditional
+	  expression.   [ruby-dev:32548]
+
 Wed Dec 12 12:11:42 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* re.c (rb_reg_regsub): should copy encoding.
diff --git a/parse.y b/parse.y
index 2f3a118d10..a57a0f407f 100644
--- a/parse.y
+++ b/parse.y
@@ -1148,7 +1148,7 @@ expr		: command_call
 		| keyword_not expr
 		    {
 		    /*%%%*/
-			$$ = call_uni_op($2, '!');
+			$$ = call_uni_op(cond($2), '!');
 		    /*%
 			$$ = dispatch2(unary, ripper_intern("not"), $2);
 		    %*/
@@ -1156,7 +1156,7 @@ expr		: command_call
 		| '!' command_call
 		    {
 		    /*%%%*/
-			$$ = call_uni_op($2, '!');
+			$$ = call_uni_op(cond($2), '!');
 		    /*%
 			$$ = dispatch2(unary, ripper_id2sym('!'), $2);
 		    %*/
@@ -2142,7 +2142,7 @@ arg		: lhs '=' arg
 		| '!' arg
 		    {
 		    /*%%%*/
-			$$ = call_uni_op($2, '!');
+			$$ = call_uni_op(cond($2), '!');
 		    /*%
 			$$ = dispatch2(unary, ID2SYM('!'), $2);
 		    %*/