In the docs, it describes the allowable string case labels as follows:

  Both ascii and wchar strings are allowed. 

Is this true?  Or are char utf-8 and dchar strings also allowed?  If not, it seems a strange restriction.

It is also unclear if compile-time-evaluable expressions are allowed for string case labels.  The general text on switches makes it seem so, but the above text moddies the waters a little, I think.