#12926: ghc master (8.1.20161202) panics with assertion failure with devel2 flavor and -O2 -------------------------------------+------------------------------------- Reporter: pacak | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 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: -------------------------------------+------------------------------------- Following code if compiled with -O2 (but not -O1) causes assertion failure. Depends only on vector. {{{#!hs {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE MultiParamTypeClasses #-} module A where import GHC.Base import qualified Data.Vector.Unboxed.Base import qualified Data.Vector.Generic.Base import Data.Vector.Generic.Mutable import qualified Data.Vector.Generic.Mutable.Base import Data.Vector.Generic (fromList) data A = A Int Int Int instance Data.Vector.Unboxed.Base.Unbox A newtype instance Data.Vector.Unboxed.Base.MVector s_a4iX A = MV_A (Data.Vector.Unboxed.Base.MVector s_a4iX (Int, Int, Int)) instance MVector Data.Vector.Unboxed.Base.MVector A where basicLength (MV_A v) = basicLength v basicUnsafeSlice idx len (MV_A v) = MV_A (basicUnsafeSlice idx len v) basicUnsafeNew len = (MV_A `liftM` (basicUnsafeNew len)) basicUnsafeWrite (MV_A v) idx val_a4iW = basicUnsafeWrite v idx ( (\ (A a_a4iT b_a4iU c_a4iV) -> (a_a4iT, b_a4iU, c_a4iV)) val_a4iW) newtype instance Data.Vector.Unboxed.Base.Vector A = V_A (Data.Vector.Unboxed.Base.Vector (Int, Int, Int)) instance Data.Vector.Generic.Base.Vector Data.Vector.Unboxed.Base.Vector A where mkA :: Data.Vector.Unboxed.Base.Vector A mkA = fromList [] }}} {{{ ghc: panic! (the 'impossible' happened) [7/1644] (GHC version 8.1.20161202 for x86_64-unknown-linux): ASSERT failed! in_scope InScope {wild_00 eta_X1T $cbasicUnsafeFreeze_a6sr $cbasicUnsafeThaw_a6st $cbasicLength_a6sv $cbasicUnsafeSlice_a6sx $cbasicUnsafeIndexM_a6sz $cbasicUnsafeCopy_a6sF $celemseq_a6t3 $cbasicLength_a6tm $cbasicUnsafeSlice_a6ty $cbasicOverlaps_a6tL $cbasicUnsafeNew_a6tN $cbasicInitialize_a6uj $cbasicUnsafeReplicate_a6up $cbasicUnsafeRead_a6uJ $cbasicUnsafeWrite_a6uL $cbasicClear_a6vg $cbasicSet_a6vE $cbasicUnsafeCopy_a6w2 $cbasicUnsafeMove_a6wr $cbasicUnsafeGrow_a6wQ wild_a7QO dt_a7QQ ds1_a7QR ds2_a7QS ds3_a7QT wild_a80U x_a819 xs1_a81a ds4_a84V z_a84W s7_a84X ds5_a851 wild5_a85V v3_a85X i_a85Y wild7_a866 x_a868 y_a86k wild9_a86m $tcA $trModule $tc'A $fVectorVectorA $fUnboxA $fMVectorMVectorA mkA $cbasicUnsafeSlice_s7QF $trModule_s7Su $trModule_s7Sv $tc'A_s7Sw $s$dmbasicUnsafeGrow_s7Vp $s$dmbasicUnsafeMove_s7Vw $s$dmbasicUnsafeReplicate_s7VB $s$dmbasicSet_s7VG $s$dmbasicUnsafeCopy_s7VN $s$dmbasicUnsafeCopy_s7VW $sunstream_s886 $s$fMVectorMVector(,,)_$cbasicUnsafeNew_s896 $s$fMVectorMVector(,,)_$cbasicUnsafeWrite_s89h $s$fMVectorMVector(,,)_$cbasicUnsafeSlice_s89k $s$fMVectorMVector(,,)_$cbasicLength_s89l $sfromList_s89m $snew_s89n $s$dmelemseq_s89o $s$dmbasicClear_s89p lvl_s89Y $j_sa8p lvl_sbhM lvl_sbhN lvl_sbhO lvl_sbhP lvl_sbhQ lvl_sbhR lvl_sbhT lvl_sbhU lvl_sbhV lvl_sbhW lvl_sbi1 lvl_sbi2 lvl_sbi4 lvl_sbi5 lvl_sbi6 lvl_sbi7 foldlM_loop_sbns foldlM_loop_sbnL lvl_sbo2 $sfoldlM_loop_sbHS $s$j_sbI5 $sfoldlM_loop_sbIa $sfoldlM_loop_sbIx} tenv [] tenvFVs [] cenv [sbHY :-> sg_sbHY] cenvFVs [sbHY :-> sg_sbHY] tys [PrimState (ST RealWorld)] cos [] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1114:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1163:22 in ghc:Outputable assertPprPanic, called at compiler/types/TyCoRep.hs:2023:56 in ghc:TyCoRep checkValidSubst, called at compiler/types/TyCoRep.hs:2056:17 in ghc:TyCoRep substTy, called at compiler/types/Coercion.hs:1457:33 in ghc:Coercion Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1114:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1118:37 in ghc:Outputable pprPanic, called at compiler/utils/Outputable.hs:1161:5 in ghc:Outputable assertPprPanic, called at compiler/types/TyCoRep.hs:2023:56 in ghc:TyCoRep checkValidSubst, called at compiler/types/TyCoRep.hs:2056:17 in ghc:TyCoRep substTy, called at compiler/types/Coercion.hs:1457:33 in ghc:Coercion Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12926 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler