Result of CTFE should be implicitly castable to immutable

[Steven Schveighoffer]

On 10/11/17 10:30 AM, 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?

100% agree. Any CTFE'd result is implicitly unique. In fact CTFE 
annoyingly makes everything unique, even where it doesn't have to!

Please file enhancement request if not already.

-Steve