diff --git a/array.c b/array.c
index 84c386cefa..6fda047e53 100644
--- a/array.c
+++ b/array.c
@@ -4197,8 +4197,8 @@ flatten(VALUE ary, int level, int *modified)
 
 /*
  *  call-seq:
- *     ary.flatten!        -> Array or nil
- *     ary.flatten!(level) -> Array or nil
+ *     ary.flatten!        -> ary or nil
+ *     ary.flatten!(level) -> ary or nil
  *
  *  Flattens +self+ in place.
  *
diff --git a/hash.c b/hash.c
index a2261bdf93..9a0f71db9a 100644
--- a/hash.c
+++ b/hash.c
@@ -2697,7 +2697,7 @@ env_each_pair(VALUE ehash)
 
 /*
  * call-seq:
- *   ENV.reject! { |name, value| } -> Hash or nil
+ *   ENV.reject! { |name, value| } -> ENV or nil
  *   ENV.reject!                   -> Enumerator
  *
  * Equivalent to ENV#delete_if but returns +nil+ if no changes were made.