#10670: panic! ASSERT failed compiler/types/Type.hs line 1712 -------------------------------------+------------------------------------- Reporter: bjmprice | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Linux Architecture: x86_64 | Type of failure: Compile-time (amd64) | crash Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- The following code causes a panic when loaded into GHCi (more complicated code below makes GHC panic also) {{{#!hs {-# LANGUAGE GADTs , PolyKinds #-} module Bug where data TyConT (a::k) = TyConT String tyConTArr :: TyConT (->) tyConTArr = TyConT "(->)" data G2 c a where G2 :: TyConT a -> TyConT b -> G2 c (c a b) getT2 :: TyConT (c :: k2 -> k1 -> k) -> TyConT (a :: k) -> Maybe (G2 c a) getT2 (TyConT c) (TyConT a) = Nothing s tf = case getT2 tyConTArr tf of Just (G2 _ _) -> Nothing _ -> Nothing }}} `ghci Bug.hs` yields {{{ ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20150717 for x86_64-unknown-linux): ASSERT failed! file compiler/types/Type.hs line 1712 a_ame -> b_amf k_anj }}} And for GHC: {{{#!hs {-# LANGUAGE GADTs , PolyKinds , FlexibleInstances , TypeOperators , ScopedTypeVariables #-} module Bug2 where import Unsafe.Coerce data TyConT (a::k) = TyConT String eqTyConT :: TyConT a -> TyConT b -> Bool eqTyConT (TyConT a) (TyConT b) = a == b tyConTArr :: TyConT (->) tyConTArr = TyConT "(->)" data TypeRepT (a::k) where TRCon :: TyConT a -> TypeRepT a TRApp :: TypeRepT a -> TypeRepT b -> TypeRepT (a b) data GetAppT a where GA :: TypeRepT a -> TypeRepT b -> GetAppT (a b) getAppT :: TypeRepT a -> Maybe (GetAppT a) getAppT (TRApp a b) = Just $ GA a b getAppT _ = Nothing eqTT :: TypeRepT (a::k1) -> TypeRepT (b::k2) -> Bool eqTT (TRCon a) (TRCon b) = eqTyConT a b eqTT (TRApp c a) (TRApp d b) = eqTT c d && eqTT a b eqTT _ _ = False data G2 c a where G2 :: TypeRepT a -> TypeRepT b -> G2 c (c a b) getT2 :: TypeRepT (c :: k2 -> k1 -> k) -> TypeRepT (a :: k) -> Maybe (G2 c a) getT2 c t = do GA t' b <- getAppT t GA c' a <- getAppT t' if eqTT c c' then Just (unsafeCoerce $ G2 a b :: G2 c a) else Nothing tyRepTArr :: TypeRepT (->) tyRepTArr = TRCon tyConTArr s tf = case getT2 tyRepTArr tf of Just (G2 _ _) -> Nothing _ -> Nothing }}} `ghc Bug2.hs` yields {{{ [1 of 1] Compiling Bug2 ( Bug2.hs, Bug2.o ) ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20150717 for x86_64-unknown-linux): ASSERT failed! file compiler/types/Type.hs line 1712 a_amr -> b_ams k_a1c2 Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} This is a regression from 7.10.1 (fails at 1224bb55cac502fe04005345aad47a6bc5c4a297) `uname -a`: `Linux cam-05-unx 3.5.0-54-generic #81~precise1-Ubuntu SMP Tue Jul 15 04:02:22 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux` using GCC 4.6.3 `gcc -v` output: {{{ Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.6/lto-wrapper Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.6.3-1ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program- suffix=-4.6 --enable-shared --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable- libstdcxx-time=yes --enable-gnu-unique-object --enable-plugin --enable- objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable- checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) }}} `ghc -v Bug2.hs`: {{{ Glasgow Haskell Compiler, Version 7.11.20150717, stage 2 booted by GHC version 7.10.1 Using binary package database: /5playpen/t-bepric/ghc- build/inplace/lib/package.conf.d/package.cache Using binary package database: /home/t-bepric/.ghc/x86_64-linux-7.11.20150717/package.conf.d/package.cache wired-in package ghc-prim mapped to ghc-prim-0.4.0.0-inplace wired-in package integer-gmp mapped to integer-gmp-1.0.0.0-inplace wired-in package base mapped to base-4.8.2.0-inplace wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.10.0.0-inplace wired-in package ghc mapped to ghc-7.11.20150717-inplace wired-in package dph-seq not found. wired-in package dph-par not found. Hsc static flags: wired-in package ghc-prim mapped to ghc-prim-0.4.0.0-inplace wired-in package integer-gmp mapped to integer-gmp-1.0.0.0-inplace wired-in package base mapped to base-4.8.2.0-inplace wired-in package rts mapped to builtin_rts wired-in package template-haskell mapped to template- haskell-2.10.0.0-inplace wired-in package ghc mapped to ghc-7.11.20150717-inplace wired-in package dph-seq not found. wired-in package dph-par not found. *** Chasing dependencies: Chasing modules from: *Bug2.hs Stable obj: [] Stable BCO: [] Ready for upsweep [NONREC ModSummary { ms_hs_date = 2015-07-22 15:01:01 UTC ms_mod = Bug2, ms_textual_imps = [import (implicit) Prelude, import Unsafe.Coerce] ms_srcimps = [] }] *** Deleting temp files: Deleting: compile: input file Bug2.hs Created temporary directory: /tmp/ghc33699_0 *** Checking old interface for Bug2: [1 of 1] Compiling Bug2 ( Bug2.hs, Bug2.o ) *** Parser: *** Renamer/typechecker: *** Desugar: Result size of Desugar (before optimization) = {terms: 206, types: 667, coercions: 24} Result size of Desugar (after optimization) = {terms: 133, types: 421, coercions: 10} *** Simplifier: *** Deleting temp files: Deleting: /tmp/ghc33699_0/ghc_1.s Warning: deleting non-existent /tmp/ghc33699_0/ghc_1.s *** Deleting temp dirs: Deleting: /tmp/ghc33699_0 ghc-stage2: panic! (the 'impossible' happened) (GHC version 7.11.20150717 for x86_64-unknown-linux): ASSERT failed! file compiler/types/Type.hs line 1712 a_amr -> b_ams k_a1c2 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10670 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler