bug#34722: 26.1; REGRESSION: `indent-pp-sexp' Wrong type argument: consp, nil

[Drew Adams]

> > 1. emacs -Q
> >
> > 2. C-x C-f foo.el
> >
> > 3. Enter this text. Be sure to hit RET after the final right paren,
> so there is a newline char at the end.
> >
> > (defun foo ()
> >   (unless t 42)))
> >
> >
> > 4. Put point just before the first left paren, then use `C-M-q'.
> >
> > This error is raised:
> >
> > Wrong type argument: consp, nil
> 
> FWIW, I cannot reproduce this with today's Emacs 27.  Your Emacs 27
> build is almost a year old, maybe we had a bug back then.

Good, if it's fixed.

Can you at least repro it in Emacs 26?  That will tell
you whether the instructions are clear enough and you
followed them OK.