Stefan Monnier <monnier@iro.umontreal.ca> schrieb am Mon Feb 23 2015 at
23:32:20:

> >> Another problem is that defvar may simply never be called.
> > But isn't it a bug to run-hooks a variable that was never explicitly
> > defined?
>
> All hook functions have always treated "unbound" as equal to nil, so no,
> it's not considered a bug to run a hook that's still unbound.
>
> Basically, given that "unbound == nil", what is a bug is to defvar
> a hook with a non-nil default value, unless that hook is predefined
> (i.e. is never unbound).
>
>
Is this something the byte compiler could warn about? At least normal hooks
by convention end in "-hook", so a warning could be emitted every time such
a variable is defined that doesn't have nil as default.