#13689: Data.Either doesn't export INLINABLE short functions like "rights" -------------------------------------+------------------------------------- Reporter: varosi | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: Component: Core Libraries | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect API | Unknown/Multiple annotation | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3576 Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata):
It just so happens that list comprehensions are directly desugared into fusion primitives and consequently produce rather large Core.
Oh, annoying. What if the implementation was ``` lefts = concatMap go where go (Left x) = [x] go (Right _) = [] ``` That should result in the same code in terms of `foldr` and `buildr`, but maybe produce a smaller unfolding, and be inlinable by itself. (This is more out of curiosity, it is not too bad to have a large unfolding, I think). Although it would be desirable to use a single library defined definition of `lefts` when no fusion happens, instead of repeating the code at every use-site. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13689#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler