twitter/effectivescala — pull request #2 by joa (2012-02-08 08:59:24+00:00)
Title: "sealed abstract" is not necessary since "sealed" is enough.

Removed "abstract" from "sealed abstract" since it is somewhat confusing.
A trait is abstract by definition so there is no need to declare it abstract again.

```sealed trait A
case object B extends A
case object C extends A```

is the same as

```sealed abstract trait A
case object B extends A
case object C extends A```