#9792: map/coerce rule never seems to fire -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: ekmett Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: Core | Version: 7.9 Libraries | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Unknown Unknown/Multiple | Blocked By: Type of failure: Runtime | Related Tickets: performance bug | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by dfeuer): I think the `map` rewrite probably isn't a big problem, because if `map` fuses with anything, the mapped coercion will become free (if a mapped coercion fuses with another mapped coercion, those will end up a mapped composed coercion—that might need some special treatment, but I'm not sure). The expansion of `coerce`, however, which seems to relate to the fact that `Coercible` has only one member, looks problematic. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9792#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler