Result of CTFE should be implicitly castable to immutable

[Michael V. Franklin]

On Wednesday, 11 October 2017 at 14:30:54 UTC, Dmitry Olshansky 
wrote:
> My motivation is, of course, std.regex.
>
> static immutable r = regex("abc");
>
> This is perfectly fine but because in general there is some 
> amount of impurtiy in regex and it won't work. Yet regex is 
> called at CTFE so there is no way it can escape mutable pointer 
> to its result.
>
> Thoughts?

For whatever it's worth, I also agree.

Mike