diff --git a/array.c b/array.c
index dbcc09d22b..fe86374db1 100644
--- a/array.c
+++ b/array.c
@@ -5828,7 +5828,7 @@ rb_ary_any_p(int argc, VALUE *argv, VALUE ary)
  *   [42, {foo: :bar}].dig(1, :foo)    #=> :bar
  */
 
-VALUE
+static VALUE
 rb_ary_dig(int argc, VALUE *argv, VALUE self)
 {
     rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
diff --git a/hash.c b/hash.c
index c8125a0d6c..af094cca90 100644
--- a/hash.c
+++ b/hash.c
@@ -3065,7 +3065,7 @@ rb_hash_any_p(int argc, VALUE *argv, VALUE hash)
  *   g.dig(:foo, :bar)           #=> TypeError: no implicit conversion of Symbol into Integer
  */
 
-VALUE
+static VALUE
 rb_hash_dig(int argc, VALUE *argv, VALUE self)
 {
     rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);