Error happens when parsing the json file

[wupco]

Hi!

SAVER throws this error:

- Reading error report from /home/xx/saver-1.0/infer/bin/b.json!
Uncaught Internal Error: ("Yojson.Basic.Util.Type_error(\"Expected string, got null\", 870828711)")
Error backtrace:
Raised at file "util.ml", line 15, characters 20-60
Called from file "util.ml" (inlined), line 95, characters 10-43
Called from file "util.ml" (inlined), line 19, characters 13-19
Called from file "src/saver/errReport.ml", line 309, characters 4-42
Called from file "src/saver/errReport.ml", line 386, characters 8-214
Called from file "src/saver/saver.ml" (inlined), line 39, characters 14-50
Called from file "src/infer.ml", line 281, characters 11-24
Re-raised at file "src/infer.ml", line 281, characters 11-24

The json file is:

{
  "err_type": "USE_AFTER_FREE",
  "source": { "node": {"filename": "overview-example.c", "procedure": "main", "line": 15 } },
   "sink": { "node": { "filename": "overview-example.c", "procedure": "main", "line": 16 } }
}

Could you update the JSON format description in install.md? Thank you!