[m-rev.] for review: don't allow nondefault mode functions in terms

[Julien Fischer]

On Sat, 31 Oct 2015, Zoltan Somogyi wrote:

>
>
> On Sat, 31 Oct 2015 17:02:32 +1100 (AEDT), Julien Fischer <jfischer at opturion.com> wrote:
>>> What happens if it is preserved for a while, and then it is lost?
>>> Uses during the first period are fine, uses during the second period
>>> cause a crash. At the moment, we have no way to prevent that loss
>>> of information. Maybe we should consider changing the rules to
>>> outlaw not putting such nonstandard signature functions into terms,
>>> but losing the higher inst info on terms containing higher order values.
>>> Unfortunately, I am pretty sure that implementing that would be
>>> a massive pain with the current mode system implementation.
>>
>> For now, as it certainly isn't acceptable for the compiler to be
>> accepting programs that cause segmentation faults, we need to go with
>> Peter's suggestion: disallow the construction of terms with a
>> non-default mode function _as a limitation of the current
>> implementation_.
>
> By that, do you mean that the diff is ok, provided we also document
> the new limitation?

Yes.

Julien.