Hi, I believe I've finished implementing version 1 of pattern synonyms (i.e. everything described in #5144, minus the things in #8581, #8582, #8583 and #8584). I've discussed the way forward with SPJ and he suggested because of the cross-cutting nature of the patch, I should wait a reasonably long time (~1 month) after 7.8 is branched off for things to settle, and then formally submit it for review. So my question is, is there anything I can do in the meantime, in preparation for the review? The code is available at https://github.com/gergoerdi/ghc. I've also added some tests to the testsuite (https://github.com/gergoerdi/ghc-testsuite), and updated the wiki pages at https://ghc.haskell.org/trac/ghc/wiki/PatternSynonyms and https://ghc.haskell.org/trac/ghc/wiki/PatternSynonyms/Implementation. Thanks, Gergo