[DDMD] Fix Issue 10724 - Allow slice of string literal to convert to const(char)*

[yebblies]

I sorta need this for DDMD so I can strip the newline from the version file:

const(char)* _version = "v" ~ import("VERSION")[0..$-1];

http://d.puremagic.com/issues/show_bug.cgi?id=10724

[denis-sh]

IMHO, needlesly complicates the language. Any discussions/documentation for it?

[yebblies]

There is plenty of precedent for this. Do you have any reasons to justify your opinion?

[denis-sh]

Do you have any reasons to justify your opinion?

No. If it is obviously legitimate for you and doesn't need any discussion I will agree. But documentation is needed.

[yebblies]

Ok. To me, this is an extension of the existing string literal -> const char* + zero termination rule. I think it is reasonable to apply this to the result of constant folding.