#14777: panic when using a function defined in terms of `error` -------------------------------------+------------------------------------- Reporter: zilinc | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Resolution: | Keywords: Operating System: Linux | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by zilinc): More experiments: after I made the following changes: {{{ diff --git a/cogent/src/Cogent/Desugar.hs b/cogent/src/Cogent/Desugar.hs index bdea312..3b8440d 100644 --- a/cogent/src/Cogent/Desugar.hs +++ b/cogent/src/Cogent/Desugar.hs @@ -175,9 +175,11 @@ pragmaToNote (_:pragmas) fn note = pragmaToNote pragmas fn note -- ----------------------------------------------------------------------------- lamLftTlv :: S.TopLevel S.RawType B.TypedPatn B.TypedExpr - -> DS t v (S.TopLevel S.RawType B.TypedPatn B.TypedExpr) -lamLftTlv (S.FunDef fn sigma alts) = undefined + -> DS t v (S.TopLevel S.RawType B.TypedPatn B.TypedExpr) +lamLftTlv (S.FunDef fn sigma alts) = S.FunDef fn sigma <$> mapM lamLftAlt alts +lamLftAlt :: S.Alt B.TypedPatn B.TypedExpr -> DS t v (S.Alt B.TypedPatn B.TypedExpr) +lamLftAlt (S.Alt p l e) = S.Alt p l <$> lamLftExpr e lamLftExpr :: B.TypedExpr -> DS t v B.TypedExpr lamLftExpr (B.TE t (S.Lam p mt e) l) = do @@ -192,6 +194,7 @@ lamLftExpr (B.TE t (S.Lam p mt e) l) = do let fn = S.FunDef f (S.PT [] t) [S.Alt (B.TP (S.PIrrefutable p) noPos) Regular e] -- no let-generalisation lftFun %= (fn:) return $ B.TE t (S.TypeApp f [] S.NoInline) l +lamLftExpr (B.TE t e l) = B.TE t <$> traverse lamLftExpr e <*> pure l -- freeVars :: B.TypedExpr -> Vec v VarName -> [(VarName, S.RawType)] -- freeVars (B.TE t (S.Var v) _) vs = maybeToList $ case findIx v vs of Just i -> Nothing; Nothing -> Just (v,t) @@ -479,7 +482,7 @@ desugarExpr (B.TE t@(S.RT (S.TVariant ts)) (S.Con c es) l) = do desugarExpr (B.TE _ (S.Seq e1 e2) _) = do v <- freshVar E <$> (Let v <$> desugarExpr e1 <*> withBinding v (desugarExpr e2)) -desugarExpr (B.TE _ (S.Lam p mt e) _) = undefined +desugarExpr (B.TE _ (S.Lam p mt e) _) = __impossible "desugarExpr (Lam)" desugarExpr (B.TE _ (S.App e1 e2) _) = E <$> (App <$> desugarExpr e1 <*> desugarExpr e2) desugarExpr (B.TE _ (S.If c [] th el) _) = E <$> (If <$> desugarExpr c <*> desugarExpr th <*> desugarExpr el) desugarExpr (B.TE _ (S.If c vs th el) _) = do }}} It doesn't crash with the `__impossible`, but this time it crashes with the `undefined`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14777#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler