Re: Redisplay hook error backtraces

[Stefan Monnier]

>> Aren't they all go through safe_call?
>
> They do, yes, but so do other things that we don't want to engage the
> backtrace mechanism for.

Actually, I'm not sure that's the case.  Basically the question is
whether `safe_call` is used because we don't care about any errors that
might be thrown (akin to ignore-errors`) or whether we do care but don't
want to let them escape and ruin our lunch (akin to
`with-demoted-errors`).

Being in redisplay is usually a good reason why we don't want to let
errors escape, even we do care about those errors (and hence we need
to use a mechanism like the one you're implementing in order to debug
those problems), but there can be other such cases that also use
`safe_call` and where we would also want to use your new code.


        Stefan