This looks like a regression to me. Positioning it on the casedef is quite vague and would lead to ambiguous errors if you have more than one `_*` in a single pattern. E.g.: 

```
t421.scala:6: error: star patterns must correspond with varargs parameters
    case (Bar1("foo",_*), Bar2("foo",_*)) => sys.error("huh?");
    ^
```