Is there a rule or something else in the way Gentoo is set up that requires/states/recommends that for a package to be marked as stable it is a requirement that all dependencies also be stable?
If someone has a basically stable system and can take the time could you possibly try emerge -pvDuN rstudio and see if it's trying to pull in lots of unstable haskell packages to build rstudio-0.98.490-r1? I've had to mask the stable version and use 0.98.490 for quite a long time but I'm wondering if I have something misconfigured that' s causing this. Thanks in advance, Mark