[m-rev.] for review: decide each type's representation just once

[Peter Wang]

On Tue, 20 Feb 2018 13:35:06 +1100 (AEDT), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> 
> 
> On Thu, 15 Feb 2018 16:17:22 +1100, Peter Wang <novalazy at gmail.com> wrote:
> > You could commit it for a few days (however long it takes to produce a
> > source distribution) so that we can check for any differences on other
> > programs.
> 
> At least two ROTDs have this diff now. Has anyone found any problems?

Not me.

> I expect that most improvements to type representation will have the effect
> of requiring a program to be compiled either (a) entirely with a compiler
> that does not have the improvement, or (b) entirely with a compiler
> that *does* have the improvement. If some modules are compiled
> with one kind of compiler and some module are compiled with the other,
> then modules on differing sides of the divide will make inconsistent
> assumptions about how the affected types are represented, which means
> that the executable won't work properly.
> 
> Introducing an invisible grade component for each improvement
> seems like overkill to me. Are people ok with recompiling whole programs
> when their (manually or automatically) installed compiler changes?

That's fine.

Peter