#13242: Panic "StgCmmEnv: variable not found" with ApplicativeDo and ExistentialQuantification -------------------------------------+------------------------------------- Reporter: ljli | Owner: simonmar Type: bug | Status: new Priority: highest | Milestone: 8.0.3 Component: Compiler | Version: 8.1 Resolution: | Keywords: 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 Simon Peyton Jones <simonpj@…>): In [changeset:"254bc3357b0de673b7873f1c4cf5dfc26d0bb5f2/ghc" 254bc33/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="254bc3357b0de673b7873f1c4cf5dfc26d0bb5f2" A much nicer solution for typechecking ApplicativeDo This patch improves the code for TcMatches.tcApplicativeStmts; see the suggestion in Trac #13242 comment:9. I now use (mapM goArg args) rather than a CPS-style fold. The result is less code, easier to understand, and automatically fixes the original problem in Trac #13242. See Note [ApplicativeDo and constraints]. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13242#comment:14> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler