I don’t know, but my instinct is to stick to the monomorphic version for now, it that’s all you need. Simon From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of Alan & Kim Zimmerman Sent: 20 October 2017 18:33 To: ghc-devs@haskell.org Subject: haddock specializeInstHead I am working the next stage of Trees that Grow into GHC [1], and need to update Haddock. The `Specialize` module[2] exports a single function, `specializeInstHead` which is called once, specialised to `GhcRn`. So all it needs to be for haddock use is specializeInstHead :: InstHead GhcRn -> InstHead GhcRn But the entire module is polymorphic in the AST parameter, so it has the following instead specializeInstHead :: (Ord (IdP name), DataId name, SetName (IdP name), NamedThing (IdP name)) => InstHead name -> InstHead name Question: does it need to be so polymorphic? I am hitting issues getting the type parameter change worked through, and it seems a bit pointless to slog on with it if it is unnecessary. Alan [1] https://github.com/ghc/ghc/tree/wip/ttg-2017-10-13https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc%2Fghc%2Ftree%2Fwip%2Fttg-2017-10-13&data=02%7C01%7Csimonpj%40microsoft.com%7C26b5b86e96f145f964ce08d517e0cc6e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636441176634035520&sdata=EU40hO%2FHQ70tAYkU1djv8e5wYNyHhw%2BTQImO3wzUer0%3D&reserved=0 [2] https://github.com/haskell/haddock/blob/a5bdb46185b7c0b3fced9a7fac9a62883d9d...https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fhaskell%2Fhaddock%2Fblob%2Fa5bdb46185b7c0b3fced9a7fac9a62883d9d57b7%2Fhaddock-api%2Fsrc%2FHaddock%2FInterface%2FSpecialize.hs%23L87&data=02%7C01%7Csimonpj%40microsoft.com%7C26b5b86e96f145f964ce08d517e0cc6e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636441176634035520&sdata=zgUxljZMi2uml5nHRrtj%2B3mcoQq7%2BFUFxbJzEqpHC5Y%3D&reserved=0