#9848: List.all does not fuse -------------------------------------+------------------------------------- Reporter: klapaucius | Owner: ekmett Type: bug | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by akio): It looks like the problem is in how `foldMap` for lists is defined. Now `all` is defined in terms of `foldMap`, and `foldMap` is defined in terms of `foldr`. However, the unfolding for `foldMap` for lists contains a recursive function, rather than a reference to `foldr`. This means any list function defined in terms of `foldMap` has no chance of fusion. Adding an INLINE pragma to the default definition for `foldMap` seems to fix the issue. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9848#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler