#8743: The impossible happened : Prelude.(!!): index too large ---------------------------------------+---------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 (amd64) Type of failure: Compile-time crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------------+---------------------------------- Comment (by goldfire): I have a terrible feeling this one is my fault. (I wrote code using `!!` in !TcIface.) But I can't build HEAD (see #8744) to find out. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8743: The impossible happened : Prelude.(!!): index too large ---------------------------------------+---------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 (amd64) Type of failure: Compile-time crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------------+---------------------------------- Comment (by rwbarton): Okay, success. {{{ *** Exception (reporting due to +RTS -xc): (THUNK_1_0), stack trace: GHC.List.CAF --> evaluated by: WwLib.deepSplitCprType_maybe.con, called from WwLib.mkWWcpr, called from WwLib.mkWwBodies, called from WorkWrap.splitFun, called from WorkWrap.splitFun, called from WorkWrap.tryWW.doSplit, called from WorkWrap.wwBind, called from WorkWrap.wwTopBinds, called from WorkWrap.wwTopBinds, called from UniqSupply.initUs_, called from WorkWrap.wwTopBinds, called from WorkWrap.wwTopBinds, called from SimplCore.doPassDFU, called from ... }}} The offending code is {{{#!haskell deepSplitCprType_maybe fam_envs con_tag ty | let (co, ty1) = topNormaliseType_maybe fam_envs ty `orElse` (mkReflCo Representational ty, ty) , Just (tc, tc_args) <- splitTyConApp_maybe ty1 , isDataTyCon tc , let cons = tyConDataCons tc con = ASSERT( cons `lengthAtLeast` con_tag ) cons !! (con_tag - fIRST_TAG) = Just (con, tc_args, dataConInstArgTys con tc_args, co) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8743: The impossible happened : Prelude.(!!): index too large ---------------------------------------+---------------------------------- Reporter: erikd | Owner: nomeata Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 (amd64) Type of failure: Compile-time crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------------+---------------------------------- Comment (by Joachim Breitner ): In [changeset:"c3ff5f29c80680a09c7779aee2535fa64b880cd9/ghc"]: {{{ #!CommitTicketReference repository="ghc" revision="c3ff5f29c80680a09c7779aee2535fa64b880cd9" Add test case for #8743 which only occurs when the instance being compiled is also present from a .hs-boot file. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8743: The impossible happened : Prelude.(!!): index too large ---------------------------------------+---------------------------------- Reporter: erikd | Owner: nomeata Type: bug | Status: merge Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 (amd64) Type of failure: Compile-time crash | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------------+---------------------------------- Changes (by nomeata): * status: new => merge Comment: Test case added and the obvious fix applied; please merge to 7.8. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8743: The impossible happened : Prelude.(!!): index too large -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by ezyang): * owner: nomeata => * status: closed => new * resolution: fixed => Comment: After adjusting the test-case to not do a direct import of the hs-boot file, I now get this Core Lint error: {{{ Compile failed (status 256) errors were: *** Core Lint errors : in result of Simplifier *** T8743.hs-boot:3:10: warning: [RHS of $fxToRowMaybe :: forall a_anp. ToRow (Maybe a_anp)] idArity 1 exceeds typeArity 0: $fxToRowMaybe *** Offending Program *** $ctoRow_awT :: forall a_awR. Maybe a_awR -> [()] [LclId, Arity=1, Str=DmdType, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True)}] $ctoRow_awT = \ (@ a_awR) (ds_dx0 :: Maybe a_awR) -> case ds_dx0 of _ [Occ=Dead] { __DEFAULT -> : @ () () ([] @ ()) } $fToRowMaybe [InlPrag=INLINE (sat-args=0)] :: forall a_awP. ToRow (Maybe a_awP) [LclIdX[DFunId(nt)], Arity=1, Str=DmdType, Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=0,unsat_ok=False,boring_ok=True) Tmpl= $ctoRow_awT `cast` (forall a_awR. Sym (NTCo:ToRow[0] <Maybe a_awR>_N) :: (forall a_awR. Maybe a_awR -> [()]) ~R# (forall a_awR. ToRow (Maybe a_awR)))}] $fToRowMaybe = $ctoRow_awT `cast` (forall a_awR. Sym (NTCo:ToRow[0] <Maybe a_awR>_N) :: (forall a_awR. Maybe a_awR -> [()]) ~R# (forall a_awR. ToRow (Maybe a_awR))) $fxToRowMaybe :: forall a_anp. ToRow (Maybe a_anp) [LclIdX, Arity=1, Str=DmdType, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=0,unsat_ok=True,boring_ok=True)}] $fxToRowMaybe = $fToRowMaybe *** End of Offense *** }}} Do not know enough to investigate further. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8743: The impossible happened : Prelude.(!!): index too large -------------------------------------+------------------------------------- Reporter: erikd | Owner: nomeata Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by ezyang): * owner: => nomeata -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#8743: The impossible happened : Prelude.(!!): index too large -------------------------------------+------------------------------------- Reporter: erikd | Owner: nomeata Type: bug | Status: new Priority: highest | Milestone: 7.8.1 Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by nomeata): I indeed was confused. The test is already marked as `expect_broken`, and you are trying to fix the breakage... But it still is unrelated to the demand analyzer. I’ll continue the discussion in #10182, where it belongs. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8743#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler