From 8d496dc3d018f9cb908134ab7c5ed7edea6e7318 Mon Sep 17 00:00:00 2001
From: gingerBill <bill@gingerbill.org>
Date: Wed, 6 Mar 2024 14:51:56 +0000
Subject: [PATCH] Fix #3173

---
 core/encoding/json/marshal.odin | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/core/encoding/json/marshal.odin b/core/encoding/json/marshal.odin
index 6596621e8..775f78748 100644
--- a/core/encoding/json/marshal.odin
+++ b/core/encoding/json/marshal.odin
@@ -382,6 +382,11 @@ marshal_to_writer :: proc(w: io.Writer, v: any, opt: ^Marshal_Options) -> (err:
 		opt_write_end(w, opt, '}') or_return
 
 	case runtime.Type_Info_Union:
+		if len(info.variants) == 0 || v.data == nil {
+			io.write_string(w, "null") or_return
+			return nil
+		}
+
 		tag_ptr := uintptr(v.data) + info.tag_offset
 		tag_any := any{rawptr(tag_ptr), info.tag_type.id}