commit https://github.com/vim/vim/commit/fcaaae6b3fdbf3421a1ff95a25ae16d82381c39a Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jan 24 16:49:11 2016 +0100 patch 7.4.1166 Problem: Can't encode a Funcref into JSON. jsonencode() doesn't handle the same list or dict twice properly. (Nikolay Pavlov) Solution: Give an error. Reset copyID when the list or dict is finished.

--- a/src/proto/json.pro
+++ b/src/proto/json.pro
@@ -1,5 +1,4 @@
 /* json.c */
 char_u *json_encode(typval_T *val);
-void json_encode_item(garray_T *gap, typval_T *val, int copyID);
 void json_decode(js_read_T *reader, typval_T *res);
 /* vim: set ft=c : */