diff --git a/string.c b/string.c
index 48718f93ac..2ff709b0b2 100644
--- a/string.c
+++ b/string.c
@@ -2006,9 +2006,7 @@ rb_str_format_m(VALUE str, VALUE arg)
     VALUE tmp = rb_check_array_type(arg);
 
     if (!NIL_P(tmp)) {
-        const long len = RARRAY_LENINT(tmp);
-        VALUE rv = rb_str_format(len, RARRAY_CONST_PTR(tmp), str);
-        return rv;
+        return rb_str_format(RARRAY_LENINT(tmp), RARRAY_CONST_PTR(tmp), str);
     }
     return rb_str_format(1, &arg, str);
 }