#9242: Implement {-# OVERLAPPABLE #-} and {-# INCOHERENT #-} pragmas -------------------------------------+------------------------------------ Reporter: simonpj | Owner: diatchki Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by goldfire): The interaction between a hypothetical `-XNoOrphanInstances`, Safety, and overlapping instances is subtle -- the flags have to be put potentially on different modules to get the Safety requirement to work out. For this reason and in order to avoid blunt instruments, I favor also deprecating !OverlappingInstances. For the bulk of you surprised by this mysterious `-XNoOrphanInstances`, it's an idea that Edward Kmett, Gershom Bazerman, and I cooked up a few months ago. More information in due course! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9242#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler