#14070: Allow ‘unsafe’ deriving strategy, deriving code with ‘unsafeCoerce’ -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: | QuantifiedContexts Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): I will respond in full in a bit but Replying to [comment:7 RyanGlScott]:
This is important, since the `f` needs to scope over both `x` and `x'`. In your example, the `f` tucked underneath the two occurrences of the `Lens` type synonyms were distinct.
Ah yes, the million ISK question is whether GHC can coerce that automatically: or does that enter `ImpredicativeTypes` territory? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14070#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler