2 files changed, 8 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index cc5b5d1874..01275b9f36 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Dec 31 00:27:54 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* object.c (rb_to_float): prohibit conversion from nil to float.
+	  [ruby-dev:37663]
+
 Tue Dec 30 21:17:00 2008  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/mkconstants.rb: use sock_define_uconst for INADDR_*
diff --git a/object.c b/object.c
index 889a0c6d21..61aa80a014 100644
--- a/object.c
+++ b/object.c
@@ -2273,6 +2273,9 @@ rb_to_float(VALUE val)
     VALUE v;
 
     if (TYPE(val) == T_FLOAT) return val;
+    if (NIL_P(val)) {
+	rb_raise(rb_eTypeError, "can't convert nil into Float");
+    }
     v = convert_type(val, "Float", "to_f", Qtrue);
     if (TYPE(v) != T_FLOAT) {
 	const char *cname = rb_obj_classname(val);