Yeah, but I meant the calls `i?dup(immutableData)` (contrary to what I initially wrote, yes). It's weak pure (from what I understood about pure), but has no side (since all input is const). So if you aren't using the result, it is a certified useless call.

You *should* be able to get away with just:
```D
           /+m = +/dup(m);
           i = idup(i);
           m = dup(i);
           /+i = +/idup(m);
```

Seapking of which, *does* `string s = "foobar".dup;` work? You should add a test for it: