commit https://github.com/vim/vim/commit/bd4593ffb170230504500ddedabad3fad1f31291 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Jan 23 22:51:07 2016 +0100 patch 7.4.1160 Problem: No error for jsondecode('"'). Solution: Give an error message for missing double quote.

--- a/src/json.c
+++ b/src/json.c
@@ -406,6 +406,7 @@ json_decode_string(js_read_T *reader, ty
     }
     else
     {
+	EMSG(_(e_invarg));
 	res->v_type = VAR_SPECIAL;
 	res->vval.v_number = VVAL_NONE;
     }