#11524: Something is amiss with quantification in pattern synonym type signatures -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler (Type | Version: 8.0.1-rc1 checker) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by niteria): Better trace with `ghc-stage2`: {{{ ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.1.20160128 for x86_64-unknown-linux): ASSERT failed! CallStack (from ImplicitParams): assertPprPanic, called at compiler/types/TyCoRep.hs:1932:51 in ghc:TyCoRep checkValidSubst, called at compiler/types/TyCoRep.hs:1981:17 in ghc:TyCoRep substTys, called at compiler/types/TyCoRep.hs:2002:14 in ghc:TyCoRep substTheta, called at compiler/typecheck/TcPatSyn.hs:254:57 in ghc:TcPatSyn in_scope InScope {k_aB3 k_aB8 a_aB9 b_aBa} tenv [auD :-> a_aB9[tau:5], auE :-> b_aBa[tau:5], aB2 :-> k_aB8[tau:5]] cenv [] tys [fun_auC[sk] ~ a_auD[sk] b_auE[sk]] cos [] needInScope [auC :-> fun_auC[sk], aB3 :-> k_aB3[tau:1]] }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11524#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler