https://issues.dlang.org/show_bug.cgi?id=19566

          Issue ID: 19566
           Summary: Warn when the same argument is passed two times, once
                    as ref or out, the other not
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: b2.temp@gmx.com

stuff like this:


```
void stuff(I,O)(const I input, ref O output){}

void other()
{
    ubyte[] data;
    stuff(data, data);
}
```

are probably a problem and worth a warn, even if `input` is not const.

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