Frontend Plugins Proposal

4 years ago Edsko proposed a patch to add support for frontend plugins to GHC. You can read his proposal here - https://ghc.haskell.org/trac/ghc/wiki/FrontendPluginsProposal#no1 Something like core to core plugins but for typechecked code would be useful for tool writers. Does anyone know why the patch was never merged? Confusingly Edward Yang implemented another feature called frontend plugins which does something quite different (allowing users to write custom major modes rather than hook into the frontend). These features are quite different to each other. Thanks, Matt