Instantiating traits with generics that extend traits with generics does not compile

Groovy 2.3.0-beta-2 does not compile programs where a generic trait extends another generic traits with that same parameter.

I have put an example project that does not compile on Github at:

https://github.com/mperry/bug-trait-generic-inheritance

In this case, we have the trait Applicative<M> and trait Monad<M> extends Applicative<M> with a single method named "left" that uses the type M. A class that implements Applicative compiles, but one that implements Monad does not.