Promotion of strings with numbers and bools is deprecated
---------------------------------------------------------
Any promotion of numbers and strings is deprecated and will
give a ``FutureWarning`` the main affected functionalities
are:

* `numpy.promote_types` and `numpy.result_type` which will raise
  an error in this case in the future.
* `numpy.concatenate` will raise an error when concatenating a string
  and numeric array. You can use ``dtype="S"`` to explicitly request
  a string result.
* `numpy.array` and related functions will start returning ``object``
  arrays because these functions use ``object`` as a fallback when
  no common dtype can be found. (In this case setting the
  ``FutureWarning`` to be raised will unfortunately lead to the new
  behaviour)

This will mainly affect code such as::

    np.asarray(['string', 0])

and::

    np.concatenate((['string'], [0]))

in both cases adding ``dtype="U"`` or ``dtype="S"`` will give the
previous (string) result.

Comparisons, universal functions, and casting are not affected by this.