From a7f3cfb7117e3fc5753353e9cd8f436bf5bcc5bc Mon Sep 17 00:00:00 2001
From: "Yukihiro \"Matz\" Matsumoto" <matz@ruby.or.jp>
Date: Sat, 8 Mar 2025 15:49:26 +0900
Subject: [PATCH] hash.c: allow 'default_proc=nil' to clear default_proc; ref
 #6483

---
 src/hash.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/hash.c b/src/hash.c
index 390e4272e..f270134c9 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -1477,7 +1477,9 @@ mrb_hash_set_default_proc(mrb_state *mrb, mrb_value hash)
   mrb_value ifnone = mrb_get_arg1(mrb);
 
   hash_modify(mrb, hash);
-  mrb_check_type(mrb, ifnone, MRB_TT_PROC);
+  if (!mrb_nil_p(ifnone)) {
+    mrb_check_type(mrb, ifnone, MRB_TT_PROC);
+  }
   mrb_iv_set(mrb, hash, MRB_SYM(ifnone), ifnone);
   if (!mrb_nil_p(ifnone)) {
     RHASH(hash)->flags |= MRB_HASH_PROC_DEFAULT;