diff --git a/ChangeLog b/ChangeLog
index 33b9b9ecee..3943d10b62 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Dec  5 12:38:48 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* compile.c (iseq_set_sequence): uses rb_compile_warning() for
+	  warning at compilation time.
+
 Fri Dec  5 12:35:46 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* compile.c (ruby_iseq_compile, ruby_iseq_translate_threaded_code),
diff --git a/compile.c b/compile.c
index 62021c8908..7f3f53b45d 100644
--- a/compile.c
+++ b/compile.c
@@ -1355,7 +1355,8 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *anchor)
 				    rb_hash_aset(map, obj, INT2FIX(lobj->position - (pos+len)));
 				}
 				else {
-				    rb_warning("duplicated when clause is ignored");
+				    rb_compile_warning(RSTRING_PTR(iseq->filename), iobj->line_no,
+						       "duplicated when clause is ignored");
 				}
 			    }
 			    generated_iseq[pos + 1 + j] = map;