It occurred to me that rather than moving just these instances to a new module, we could move the large tuples themselves to a new module Data.LargeTuple and put the instances there. The Prelude would reexport
#13072: Move large tuples to a separate module in base -------------------------------------+------------------------------------- Reporter: rwbarton | Owner: Type: task | Status: new Priority: normal | Milestone: 8.2.1 Component: | Version: 8.1 libraries/base | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Quoting from my message to ghc-devs@: the large tuples, so there would be no user-visible change. According to my experiments, GHC should never have to read the Data.LargeTuple interface file unless a program actually mentions a large tuple type, which is presumably rare. We could then also extend the existing instances for Eq, Show, etc., which are currently only provided through 15-tuples.
A nontrivial aspect of this change is that tuples are wired-in types,
and they currently all live in the ghc-prim package. I'm actually not sure why they need to be wired-in rather than ordinary types with a funny- looking name. In any case I need to look into this further, but the difficulties here don't seem to be insurmountable. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13072 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler