#2439: Missed optimisation with dictionaries and loops ---------------------------------+------------------------------------------ Reporter: rl | Owner: simonpj Type: bug | Status: new Priority: lowest | Milestone: 7.6.2 Component: Compiler | Version: 6.9 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: Runtime performance bug Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Comment(by simonpj): Can you explain eaxtly how making single-method classes be a data type would break edward's library? And example where forcing a single method would be bad: {{{ class C a where foo :: a instance C Int where foo = undefined bar :: C a => Int -> Int bar x = x main = print (bar (3 :: Int)) }}} -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/2439#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler