encoding/json: error message for nested encoding is not specific enough #34327
for the above code, error message return by library is
but better message could have been
The error message in 1.13 is much better (https://play.golang.org/p/UD-bFXMEWHh) with
I think this commit (29bc4f1) fixes this, but I don't think it is worth backporting an error message improvement.