[ESS] Trouble evaluating in namespace

[Vitalie Spinu]

You cannot evaluate your input line by line inside a package. The entire
function should be sent at once. Use C-c C-c instead.

The current doc string of `ess-eval-region-or-line-visibly-and-step` says:

  Note that when inside a package and namespaced evaluation is in place (see
  ‘ess-r-set-evaluation-env’) evaluation of multiline input will fail.

>> On Thu, Dec 06 2018 16:07, Kevin Wright via ESS-help wrote:

>  (ess-inject-source nil)

Not the best idea. At least for functions you would like to have source
references on errors. There is really no benefits at all for changing the
default to nil.

  Vitalie