Adding a new constructor will force TH clients to implement handling of infix constructors even in situations where they don't care about infixity, whereas adding a new field to `GadtC` will be simple to handle -
#11345: Template Haskell's handling of infix GADT constructors is broken -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: RyanGlScott Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 8.1 Resolution: | Keywords: 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): Replying to [comment:2 jstolarek]: programmers can simply ignore that field in situations where it is irrelevant. Fair enough. By that logic, we don't need `InfixC` either, but I'll avoid making breaking changes for now. Let's see if I can get this done by the 8.0 release—fingers crossed! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11345#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler