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.