#16310: Program fails with "Impossible case alternative" when optimized -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Resolution: wontfix | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Runtime crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Replying to [comment:6 goldfire]:
But perhaps it would be better to put the use of `unsafeCoerce` in `funExt` directly. I wonder if that quells the problem.
Alas, defining `funExt _ = unsafeCoerce (Refl @f)` does no good—it still produces `Impossible case alternative` when ran. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16310#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler