#15517: -O0 and pattern synonyms triggers panic in trimJoinCont -------------------------------------+------------------------------------- Reporter: sjakobi | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I've attached the output of running `/opt/ghc/8.4.3/bin/ghc Bug.hs -dcore- lint -O0 -fforce-recomp`. The highlight is: {{{ [1 of 1] Compiling Generics.MRSOP.Examples.RoseTreeTH ( Bug.hs, Bug.o ) *** Core Lint errors : in result of Simplifier *** <no location info>: warning: [RHS of fail_a1dN :: Void# -> El FamRoseInt ix_a1en -> Rep Singl (El FamRoseInt) (Lkup ix_a1en CodesRoseInt)] idArity 2 exceeds arity imposed by the strictness signature <L,U>x: fail_a1dN }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15517#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler