Re: [GHC] #13547: ghc: panic! StgCmmEnv: variable not found

10 Apr 2017

      #13547: ghc: panic! StgCmmEnv: variable not found
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        Reporter:  cipher1024        |                Owner:  (none)
            Type:  bug               |               Status:  infoneeded
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
  (CodeGen)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  10158             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Here is a much smaller test case.  Still a big mess of applicative do and
 arrows, neither of which I am familiar with, alas.
 {{{
 {-# LANGUAGE Arrows #-}
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE DeriveFunctor #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE KindSignatures #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE UndecidableInstances #-}

 module Document.Phase.Proofs2 (step) where

 import Control.Applicative
 import Control.Arrow
 import Control.Category

 import Control.Monad
 import Data.Functor.Compose
 import Data.Maybe
 import Data.Proxy
 import Data.Typeable

 import GHC.Exts (Constraint)

 import Prelude hiding (id,(.))

 data Inference rule
 data MachineP3
 data RawProgressProp

 data Cell1 (f :: * -> *) (constr :: * -> Constraint)
    = forall a. (constr a, Typeable a) => Cell (f a)

 data Inst1 f constr a = (Typeable a,constr a) => Inst (f a)

 newtype RuleProxy = RuleProxy { _ruleProxyCell :: Cell1 Proxy RuleParser }

 type VoidInference = Cell1 (Compose Inference Proxy) RuleParser

 class Monad m => MonadReader r m | m -> r where

 instance MonadReader r ((->) r) where

 class RuleParser rule where

 type Lens' s a = Lens s s a a
 type Lens s t a b = forall f. Functor f => (a -> f b) -> s -> f t
 type Getting r s a = (a -> Const r a) -> s -> Const r s

 class HasCell s a | s -> a where

 instance HasCell RuleProxy (Cell1 (Proxy :: * -> *) RuleParser) where

 data LatexParserA a g = LatexParserA
 instance Category LatexParserA where
 instance Arrow    LatexParserA  where

 -----------------------------
 stepList :: MachineP3
          -> LatexParserA (RawProgressProp,Inst1 Proxy RuleParser rule)
 VoidInference
 stepList m = error "urk"

 step :: MachineP3 -> LatexParserA (RawProgressProp,RuleProxy)
 VoidInference
 step m = insideOneEnvOf ["step","flatstep"] $ proc (goal,prxy) -> do
                 Cell prxy' <- arr (view xcell) -< prxy
                 stepList m -< (goal,Inst prxy')

 view :: MonadReader s m => Getting a s a -> m a
 view l = error "urk"

 insideOneEnvOf :: [String] -> LatexParserA a b -> LatexParserA a b
 insideOneEnvOf = error "urk"

 xcell :: HasCell s a => Lens' s a
 xcell = error "urk"
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13547#comment:22
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