#10359: Tuple constraint synonym led to asymptotic performance lossage -------------------------------------+------------------------------------- Reporter: axch | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonpj): Ah I see. Well that rules out using record update. What happens if you simulate tuple predicates, thus: {{{ class (Fractional a, Real a) => Numerical a instance (Fractional a, Real a) => Numerical a }}} I think that'll work. You need `FlexibleInstances`, `UndecidableInstances`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10359#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler