diff --git a/ChangeLog b/ChangeLog
index 3e5f79eea2..3aed430ced 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,10 +1,13 @@
-Fri Jul 13 11:16:25 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Fri Jul 13 11:17:53 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (program, stmt, primary): reduced duplicated code.
 
 	* parse.y (dsym): convert also literals containing NUL to
 	  symbol.
 
+	* parse.y (debug_lines): use rb_hash_lookup() to get rid of
+	  call of Hash#default.
+
 Fri Jul 13 10:33:29 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* array.c (rb_ary_flatten_bang): check argument if valid
diff --git a/parse.y b/parse.y
index 70c0850b37..8fdd12e17a 100644
--- a/parse.y
+++ b/parse.y
@@ -4597,7 +4597,7 @@ debug_lines(VALUE f)
 	VALUE hash = rb_const_get_at(rb_cObject, rb_intern("SCRIPT_LINES__"));
 	if (TYPE(hash) == T_HASH) {
 	    VALUE fname = rb_str_new2((const char *)f);
-	    VALUE lines = rb_hash_aref(hash, fname);
+	    VALUE lines = rb_hash_lookup(hash, fname);
 	    if (NIL_P(lines)) {
 		lines = rb_ary_new();
 		rb_hash_aset(hash, fname, lines);