#16288: Core Lint error: Occurrence is GlobalId, but binding is LocalId -------------------------------------+------------------------------------- Reporter: monoidal | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.7 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: 15840 | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Compiling the following three modules causes a Core Lint error in HEAD. (This does not happen in 8.6 - the Lint check was introduced later.) To reproduce: save the three files in `Repro/` directory and use `ghc- stage2 -dcore-lint -O Repro/B.hs`. The reproduction code is minimized version of code from cabal and prettyprint libraries. A.hs {{{ #!haskell module Repro.A where import Repro.C data License class Pretty a where pretty :: a -> Doc instance Pretty License where pretty _ = pretV bar :: (Pretty a) => a -> Doc bar w = foo (pretty (u w w w w)) u :: a -> a -> a -> a -> a u = u }}} B.hs {{{ #!haskell module Repro.B where import Repro.A import Repro.C bar2 :: License -> Doc bar2 = bar }}} C.hs {{{ #!haskell module Repro.C where data Doc = Empty | Beside Doc hcat :: Doc -> Doc hcat Empty = Empty hcat xs = hcat xs pretV = hcat Empty foo :: Doc -> Doc foo Empty = hcat Empty foo val = Beside val }}} The error: {{{ *** Core Lint errors : in result of Simplifier *** Repro/C.hs:9:1: warning: [in body of letrec with binders pretV_r3 :: Doc] Occurrence is GlobalId, but binding is LocalId pretV :: Doc [GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 20 0}] *** Offending Program *** lvl_s1kN :: Doc [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=True, Expandable=False, Guidance=IF_ARGS [] 30 20}] lvl_s1kN = case pretV of wild_Xd { Empty -> pretV; Beside ipv_s105 -> Beside wild_Xd } $sbar_s1kL [InlPrag=NOUSERINLINE[2]] :: License -> Doc [LclId, Arity=1, Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True) Tmpl= \ _ [Occ=Dead] -> case pretV of wild_Xd [Occ=Once*] { Empty -> let { pretV_r3 :: Doc [LclId] pretV_r3 = wild_Xd } in pretV; Beside _ [Occ=Dead] -> Beside wild_Xd }}] $sbar_s1kL = \ _ [Occ=Dead] -> lvl_s1kN $trModule_s1kE :: Addr# [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 20 0}] $trModule_s1kE = "main"# $trModule_s1kF :: TrName [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 20}] $trModule_s1kF = TrNameS $trModule_s1kE $trModule_s1kG :: Addr# [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 30 0}] $trModule_s1kG = "Repro.B"# $trModule_s1kH :: TrName [LclId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 20}] $trModule_s1kH = TrNameS $trModule_s1kG $trModule :: Module [LclIdX, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 30}] $trModule = Module $trModule_s1kF $trModule_s1kH bar2 :: License -> Doc [LclIdX, Arity=1, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [0] 30 20}] bar2 = \ _ [Occ=Dead] -> case pretV of wild_Xd { Empty -> pretV; Beside ipv_s105 -> Beside wild_Xd } *** End of Offense *** }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16288 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler