#12583: Deriving standalone Ix instance for GADT leads to GHC panic -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D2521 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ryan Scott <ryan.gl.scott@…>): In [changeset:"0e7ccf6d233c66b23a60de4e35e039f78ea3e162/ghc" 0e7ccf6/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="0e7ccf6d233c66b23a60de4e35e039f78ea3e162" Fix TH ppr output for list comprehensions with only one Stmt A folow-up to D2521 (which addressed #12583), where the `Outputable` `ppr` output was tweaked to display a list comprehension with only one `Stmt` as `[Foo]` instead of `[Foo|]` (which isn't valid Haskell). I forgot to update the corresponding code in `Language.Haskell.TH.Ppr` which pretty-prints `CompE`, however, so this commit takes care of that. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12583#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler