https://issues.dlang.org/show_bug.cgi?id=20548

          Issue ID: 20548
           Summary: Use bit vector instead of bool[] in RandomCover when
                    choices cannot be packed in a single word
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: phobos
          Assignee: nobody@puremagic.com
          Reporter: n8sh.secondary@hotmail.com

RandomCover has had a non-allocating optimization for small sizes since PR #6576 but for larger sizes still uses 1 byte per flag which can be improved.

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