#9371: Overlapping type families, segafult ----------------------------------------+---------------------------------- Reporter: pingu | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 (amd64) Type of failure: Runtime crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | ----------------------------------------+---------------------------------- Comment (by simonpj): OK I agree that the same issue arises if `IdentityT` was a data type, so my point about newtype unwrapping for `IdentityT` was a bit of a red herring. And yes I agree that this "silly example" is indeed a case where eta- reduction of newtype axioms (and data/newtype instance!) axioms is useful. And since the code is implemented, I suppose that the shortest path is to fix the conflict detector. But it does hurt me that we have NO formalised description of the eta- reduction story in any of our papers. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9371#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler