#11778: Preserve demandInfo on lambda binders in the simpifier -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): Just to confirm my understanding: Looking at the code, it seems the same effect could be achieved with less code change by changing {{{ need_to_zap = any zappable_bndr (drop n_args bndrs) n_args = countArgs cont }}} to {{{ need_to_zap = n_args > 0 && any zappable_bndr (drop n_args bndrs) n_args = countArgs cont }}} because the problem only occurs if there is some, but not enough beta- reduction. In particular, when simplifying the definition, `n_args` will be zero. (I’m not saying that this is a better implementation. But maybe it is, as it is more local.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11778#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler