Scala slow builds: development approaches to avoid

Question

First of all, incremental builds via SBT are pretty awesome, generally in the < 1sec range. However, sometimes you have to do a full clean/compile, or, in the case of increme

Answer 1

I've noticed that type members can force rebuilds in places you would not expect. For example:

foo.scala:

object foo {
    class A {
        type F = Float
    }
    def z: Int = 8
}

bar.scala:

object bar {
    def run { println(foo.z) }
}

Changing the value of z does not force bar to be recompiled. Changing the type of F does, even though bar never refers to F or even to A. Why, I have no idea (Scala 2.9.1).