1 files changed, 1 insertions, 1 deletions
diff --git a/string.c b/string.c
index de8e37f5d3..ce90c07d15 100644
--- a/string.c
+++ b/string.c
@@ -8052,7 +8052,7 @@ rb_str_downcase_bang(int argc, VALUE *argv, VALUE str)
 
 /*
  *  call-seq:
- *    downcase(mapping) -> string
+ *    downcase(mapping = :ascii) -> new_string
  *
  *  :include: doc/string/downcase.rdoc
  *