https://issues.dlang.org/show_bug.cgi?id=13535

          Issue ID: 13535
           Summary: byCodeUnit doesn't satisfy hasSlicing
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Phobos
          Assignee: nobody@puremagic.com
          Reporter: sinkuu@aol.jp

Currently ByCodeUnitImpl.opSlice returns an array slice to the original
(w)string, but std.range.hasSlicing requires that it returns a range of the
same type(ByCodeUnitImpl).

--