Standalone Deriving, GND and roles in 7.8.1-rc2

Hello! Trying to build random packages with fresh ghc-7.8.1-rc2 I've come up with a strange bit: https://github.com/trofi/Idris-dev/commit/9f93122ba1aa075c2fa1555fea68a6c403... Is it an intended behaviour that deriving instance Parsing IdrisInnerParser capable of doing more, than newtype IdrisInnerParser a = IdrisInnerParser { runInnerParser :: Parser a } deriving (Parsing) ? Thanks! -- Sergei