Splitting build.sbt, causes the set command to fail

The problem is explained in this Stack overflow question. I open a bug, as I receive no answers.

I have this in my build.sbt:

val myKey = settingKey[Boolean]("My key")

in the interactive console of SBT, I make this:

> set myKey in Global := true
<set>:1: error: type mismatch;
found   : Boolean(true)
required: T
myKey in Global := true

I’m using SBT 0.13.9. I think this is a bug. I could do it before.

String keys can be set normally:

set myStringKey in Global := "...."

[edit from @dwijnand, full reproduction steps in https://github.com/sbt/sbt/issues/2203#issuecomment-228872196]

[DavidPerezIngeniero]

If I change in build.sbt the value of the setting it doesn’t work either. Reloading or restarting sbt doesn’t. But if I delete project/target folder and restart SBT, then it works. So this problem is related with an incremental compilation bug.

[metasim]

@dwijnand Wow! Can’t get much more minimalist than that!