#13887: Template Haskell pretty-printer doesn't parenthesize infix datatype names in data declarations -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 8.0.1 Resolution: | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Thanks for looking into this, ak3n! I don't believe changing the implementation of `pprName` is what you want here, since that will affect far more than just infix datatypes names, which is what you really care about. I think your second suggestion (changing uses of `ppr` to `pprName' Applied`) is on the right track. As far as why the type of `Refl1_3` is pretty-printed incorrectly, I //think// it's due to the pretty-printer for `Type`. It has a case for `ConT` [https://git.haskell.org/ghc.git/blob/HEAD:/libraries/template- haskell/Language/Haskell/TH/Ppr.hs#l682 here]: {{{#!hs pprParendType (ConT c) = ppr c }}} I think this should be `pprName' Applied c` instead. This is consistent with the pretty-printer's [https://git.haskell.org/ghc.git/blob/3c4537ea1c940966eddcb9cb418bf8e39b8f0f1... /template-haskell/Language/Haskell/TH/Ppr.hs#l128 treatment] for `Exp` as well: {{{#!hs pprExp _ (ConE c) = pprName' Applied c }}} So that feels like the right solution. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13887#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler