bug#14448: Wrong indentation in comment lines for F90 mode?

[Glenn Morris]

Angelo Graziosi wrote:

> Start Emacs with
>
> $ emacs -Q &
>
> then "C-x C-f foo.f90". Now type "!" to start a comment line and then
> type M-j to produce other comment lines. The result is as follow:
>
>
> !
>   !

You reported this before.
http://debbugs.gnu.org/cgi/bugreport.cgi?bug=5595

As I said then:

  I don't understand what comment-indent-new-line is supposed to do, nor
  which variables modes should set to make it work correctly.