If port is just an int, you can just do:

```
val echoTracePortKey = TaskKey[Int](EchoTracePort)

def makeTracePortSettings(key: sbt.ScopedKey[_], port: Int): Seq[Setting[_]] = 
  Seq(echoTracePortKey in key.scope := port)
```

If it's easier to read.  The cast, at least, should not be necessary (maybe an intellij thing?)