Time for Phobos CTFE-ability unittests...right? RIGHT?

[Don]

Nick Sabalausky wrote:
> Yet again, a new DMD release has broken my code, and other people's code, 
> too, just because of Phobos functions loosing their CTFE-ability. (strip(), 
> toLower(), etc... And yes, I did bring up the strip() regression on the beta 
> list, to no effect.)

The situation is, that prior to 2.054, use of Phobos in CTFE functions 
has not been supported. No official statements have ever been made that 
it was supported (and I've tried hard to publicize the fact that it was 
not supported). There were some fundamental wrong-code bugs and severe 
limitations in CTFE. And so although some Phobos functions seemed to 
work in CTFE, most of them were not correct.
So, any Phobos function which used to work in CTFE in some old release 
but doesn't any more is not a regression. It was just dumb luck, relying 
on undefined behaviour, if any happened to work in a particular release.

This has changed with 2.054. Although there are still some restrictions 
(no classes, many builtin functions aren't implemented), the fundamental 
wrong code bugs are fixed. So any Phobos function which works in CTFE in 
2.054, but fails in a future release, can be considered a regression.
We are now in a _completely_ different regime.