[GHC] #13410: GHC HEAD regression: Template variable unbound in rewrite rule
#13410: GHC HEAD regression: Template variable unbound in rewrite rule
-------------------------------------+-------------------------------------
Reporter: RyanGlScott | Owner: (none)
Type: bug | Status: new
Priority: highest | Milestone: 8.2.1
Component: Compiler | Version: 8.1
Keywords: | Operating System: Unknown/Multiple
Architecture: | Type of failure: Compile-time
Unknown/Multiple | crash or panic
Test Case: | Blocked By:
Blocking: | Related Tickets:
Differential Rev(s): | Wiki Page:
-------------------------------------+-------------------------------------
`hybrid-vectors-0.2.1` currently fails to build with GHC HEAD. I've
attached a minimized repro file with no dependencies (it's 410 lines long,
since I had to copy-paste a lot of code from `vector` in order to
reproduce this). The attached file builds on GHC 7.10.3 and 8.0.2, but
fails on GHC HEAD with this panic:
{{{
$ ~/Software/ghc2/inplace/bin/ghc-stage2 -O2 -fforce-recomp Bug.hs
[1 of 1] Compiling Data.Vector.Hybrid.Internal ( Bug.hs, Bug.o )
Bug.hs:389:10: warning: [-Wmissing-methods]
• No explicit implementation for
‘gmbasicOverlaps’, ‘gmbasicInitialize’, and ‘gmbasicUnsafeRead’
• In the instance declaration for ‘GMVector (MVector u v) (a, b)’
|
389 | instance (GMVector u a, GMVector v b) => GMVector (MVector u v) (a,
b) where
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Bug.hs:407:10: warning: [-Wmissing-methods]
• No explicit implementation for
‘gbasicUnsafeFreeze’, ‘gbasicUnsafeThaw’, ‘gbasicLength’,
‘gbasicUnsafeSlice’, and ‘gbasicUnsafeIndexM’
• In the instance declaration for ‘GVector (Vector u v) (a, b)’
|
407 | instance (GVector u a, GVector v b) => GVector (Vector u v) (a, b)
where
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.3.20170310 for x86_64-unknown-linux):
Template variable unbound in rewrite rule
Variable: sc_s8FV
Rule "SC:$j0"
Rule bndrs: [sc_s8FV, sc_s8FW, sc_s8FX, sg_s8FY, sc_s8FU]
LHS args: [sc_s8FU,
(MV
@ (GMutable u_a4oM)
@ (GMutable v_a4oO)
@ (PrimState (ST RealWorld))
@ (a_a4oN, b_a4oP)
@ a_a4oN
@ b_a4oP
@~ (<(a_a4oN, b_a4oP)>_N
:: ((a_a4oN, b_a4oP) :: *) ~# ((a_a4oN, b_a4oP) :: *))
sc_s8FW
sc_s8FX)
`cast` (sg_s8FY
:: (MVector
(GMutable u_a4oM)
(GMutable v_a4oO)
(PrimState (ST RealWorld))
(a_a4oN, b_a4oP) :: *)
~R#
(GMutable
(Vector u_a4oM v_a4oO) (PrimState (ST
RealWorld)) c_a4oQ :: *))]
Actual args: [sc_s8FS,
wild_X3x
`cast` (Sub
(Sym (D:R:GMutableVector[0]
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * Attachment "Bug.hs" added. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by RyanGlScott: Old description:
`hybrid-vectors-0.2.1` currently fails to build with GHC HEAD. I've attached a minimized repro file with no dependencies (it's 410 lines long, since I had to copy-paste a lot of code from `vector` in order to reproduce this). The attached file builds on GHC 7.10.3 and 8.0.2, but fails on GHC HEAD with this panic:
{{{ $ ~/Software/ghc2/inplace/bin/ghc-stage2 -O2 -fforce-recomp Bug.hs [1 of 1] Compiling Data.Vector.Hybrid.Internal ( Bug.hs, Bug.o )
Bug.hs:389:10: warning: [-Wmissing-methods] • No explicit implementation for ‘gmbasicOverlaps’, ‘gmbasicInitialize’, and ‘gmbasicUnsafeRead’ • In the instance declaration for ‘GMVector (MVector u v) (a, b)’ | 389 | instance (GMVector u a, GMVector v b) => GMVector (MVector u v) (a, b) where | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Bug.hs:407:10: warning: [-Wmissing-methods] • No explicit implementation for ‘gbasicUnsafeFreeze’, ‘gbasicUnsafeThaw’, ‘gbasicLength’, ‘gbasicUnsafeSlice’, and ‘gbasicUnsafeIndexM’ • In the instance declaration for ‘GVector (Vector u v) (a, b)’ | 407 | instance (GVector u a, GVector v b) => GVector (Vector u v) (a, b) where | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.3.20170310 for x86_64-unknown-linux): Template variable unbound in rewrite rule Variable: sc_s8FV Rule "SC:$j0" Rule bndrs: [sc_s8FV, sc_s8FW, sc_s8FX, sg_s8FY, sc_s8FU] LHS args: [sc_s8FU, (MV @ (GMutable u_a4oM) @ (GMutable v_a4oO) @ (PrimState (ST RealWorld)) @ (a_a4oN, b_a4oP) @ a_a4oN @ b_a4oP @~ (<(a_a4oN, b_a4oP)>_N :: ((a_a4oN, b_a4oP) :: *) ~# ((a_a4oN, b_a4oP) :: *)) sc_s8FW sc_s8FX) `cast` (sg_s8FY :: (MVector (GMutable u_a4oM) (GMutable v_a4oO) (PrimState (ST RealWorld)) (a_a4oN, b_a4oP) :: *) ~R# (GMutable (Vector u_a4oM v_a4oO) (PrimState (ST RealWorld)) c_a4oQ :: *))] Actual args: [sc_s8FS, wild_X3x `cast` (Sub (Sym (D:R:GMutableVector[0]
_N _N)) _N (Sym cobox_a4Gz) :: (MVector (GMutable u_a4oM) (GMutable v_a4oO) (PrimState (ST RealWorld)) (a_a4oN, b_a4oP) :: *) ~R# (GMutable (Vector u_a4oM v_a4oO) (PrimState (ST RealWorld)) c_a4oQ :: *))] Call stack: CallStack (from HasCallStack): prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1191:58 in ghc:Outputable callStackDoc, called at compiler/utils/Outputable.hs:1195:37 in ghc:Outputable pprPanic, called at compiler/specialise/Rules.hs:579:19 in ghc:Rules }}} Some important things to note:
* `-O2` is required to trigger this bug; using `-O1` or below works fine. * The problematic code is the `Read (Vector u v c)` instance at the very bottom. In particular, commenting out the last line `readPrec = greadPrec` makes the panic go away. * Moreover, there's a particular `INLINE` pragma in the `GMVector (MVector u v) (a, b)` instance that is critical to triggering the panic (it's on line 394; I've added a comment `Removing this INLINE pragma makes it compile` above it).
New description:
`hybrid-vectors-0.2.1` currently fails to build with GHC HEAD. I've
attached a minimized repro file with no dependencies (it's 410 lines long,
since I had to copy-paste a lot of code from `vector` in order to
reproduce this). The attached file builds on GHC 7.10.3 and 8.0.2, but
fails on GHC HEAD with this panic:
{{{
$ ~/Software/ghc2/inplace/bin/ghc-stage2 -O2 -fforce-recomp Bug.hs
[1 of 1] Compiling Data.Vector.Hybrid.Internal ( Bug.hs, Bug.o )
Bug.hs:389:10: warning: [-Wmissing-methods]
• No explicit implementation for
‘gmbasicOverlaps’, ‘gmbasicInitialize’, and ‘gmbasicUnsafeRead’
• In the instance declaration for ‘GMVector (MVector u v) (a, b)’
|
389 | instance (GMVector u a, GMVector v b) => GMVector (MVector u v) (a,
b) where
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Bug.hs:407:10: warning: [-Wmissing-methods]
• No explicit implementation for
‘gbasicUnsafeFreeze’, ‘gbasicUnsafeThaw’, ‘gbasicLength’,
‘gbasicUnsafeSlice’, and ‘gbasicUnsafeIndexM’
• In the instance declaration for ‘GVector (Vector u v) (a, b)’
|
407 | instance (GVector u a, GVector v b) => GVector (Vector u v) (a, b)
where
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.3.20170310 for x86_64-unknown-linux):
Template variable unbound in rewrite rule
Variable: sc_s8FV
Rule "SC:$j0"
Rule bndrs: [sc_s8FV, sc_s8FW, sc_s8FX, sg_s8FY, sc_s8FU]
LHS args: [sc_s8FU,
(MV
@ (GMutable u_a4oM)
@ (GMutable v_a4oO)
@ (PrimState (ST RealWorld))
@ (a_a4oN, b_a4oP)
@ a_a4oN
@ b_a4oP
@~ (<(a_a4oN, b_a4oP)>_N
:: ((a_a4oN, b_a4oP) :: *) ~# ((a_a4oN, b_a4oP) :: *))
sc_s8FW
sc_s8FX)
`cast` (sg_s8FY
:: (MVector
(GMutable u_a4oM)
(GMutable v_a4oO)
(PrimState (ST RealWorld))
(a_a4oN, b_a4oP) :: *)
~R#
(GMutable
(Vector u_a4oM v_a4oO) (PrimState (ST
RealWorld)) c_a4oQ :: *))]
Actual args: [sc_s8FS,
wild_X3x
`cast` (Sub
(Sym (D:R:GMutableVector[0]
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * keywords: => JoinPoints Comment: Commit 8d5cf8bf584fd4849917c29d82dcf46ee75dd035 (Join points) introduced this regression. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * cc: lukemauer (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | 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 RyanGlScott): I reduced the file from ~400 lines to ~150 lines: {{{#!hs {-# LANGUAGE BangPatterns #-} {-# LANGUAGE FlexibleContexts #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE KindSignatures #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE UndecidableInstances #-} module Data.Vector.Hybrid.Internal (Vector) where import Control.Monad (liftM2) import Data.Functor.Identity (Identity(..)) import GHC.ST (ST, runST) import Text.Read (ReadPrec, readPrec) ----- class Monad m => PrimMonad m where type PrimState m instance PrimMonad (ST s) where type PrimState (ST s) = s class GMVector v a where gmbasicLength :: v s a -> Int gmbasicUnsafeSlice :: Int -> Int -> v s a -> v s a gmbasicUnsafeNew :: PrimMonad m => Int -> m (v (PrimState m) a) gmbasicUnsafeWrite :: PrimMonad m => v (PrimState m) a -> Int -> a -> m () type family GMutable (v :: * -> *) :: * -> * -> * class GMVector (GMutable v) a => GVector v a where gbasicUnsafeFreeze :: PrimMonad m => GMutable v (PrimState m) a -> m (v a) data Step s a where Yield :: a -> s -> Step s a instance Functor (Step s) where {-# INLINE fmap #-} fmap f (Yield x s) = Yield (f x) s data Stream m a = forall s. Stream (s -> m (Step s a)) s data Chunk v a = Chunk Int (forall m. (PrimMonad m, GVector v a) => GMutable v (PrimState m) a -> m ()) data New v a = New { newrun :: forall s. ST s (GMutable v s a) } type MBundle m v a = Stream m (Chunk v a) type Bundle v a = MBundle Identity v a mbfromStream :: Monad m => Stream m a -> MBundle m v a {-# INLINE mbfromStream #-} mbfromStream (Stream step t) = Stream step' t where step' s = do r <- step s return $ fmap (\x -> Chunk 1 (\v -> gmbasicUnsafeWrite v 0 x)) r mbunsafeFromList :: Monad m => [a] -> MBundle m v a {-# INLINE [1] mbunsafeFromList #-} mbunsafeFromList xs = mbfromStream (sfromList xs) blift :: Monad m => Bundle v a -> MBundle m v a {-# INLINE [1] blift #-} blift (Stream vstep t) = Stream (return . runIdentity . vstep) t sfromList :: Monad m => [a] -> Stream m a {-# INLINE sfromList #-} sfromList zs = Stream step zs where step (x:xs) = return (Yield x xs) step _ = undefined sfoldlM :: Monad m => (a -> b -> m a) -> a -> Stream m b -> m a {-# INLINE [1] sfoldlM #-} sfoldlM m w (Stream step t) = foldlM_loop w t where foldlM_loop z s = do r <- step s case r of Yield x s' -> do { z' <- m z x; foldlM_loop z' s' } gmvunstream :: (PrimMonad m, GVector v a) => Bundle v a -> m (GMutable v (PrimState m) a) {-# INLINE [1] gmvunstream #-} gmvunstream s = gmvmunstreamUnknown (blift s) gmvmunstreamUnknown :: (PrimMonad m, GVector v a) => MBundle m v a -> m (GMutable v (PrimState m) a) {-# INLINE gmvmunstreamUnknown #-} gmvmunstreamUnknown s = do v <- gmbasicUnsafeNew 0 (_, _) <- sfoldlM copyChunk (v,0) s return undefined where {-# INLINE [0] copyChunk #-} copyChunk (v,i) (Chunk n f) = do let j = i+n v' <- if gmbasicLength v < j then gmbasicUnsafeNew undefined else return v f (gmbasicUnsafeSlice i n v') return (v',j) newunstream :: GVector v a => Bundle v a -> New v a {-# INLINE [1] newunstream #-} newunstream s = s `seq` New (gmvunstream s) gnew :: GVector v a => New v a -> v a {-# INLINE [1] gnew #-} gnew m = m `seq` runST (gbasicUnsafeFreeze =<< newrun m) gunstream :: GVector v a => Bundle v a -> v a {-# INLINE gunstream #-} gunstream s = gnew (newunstream s) gfromList :: GVector v a => [a] -> v a {-# INLINE gfromList #-} gfromList = gunstream . mbunsafeFromList greadPrec :: (GVector v a, Read a) => ReadPrec (v a) {-# INLINE greadPrec #-} greadPrec = do xs <- readPrec return (gfromList xs) ----- data MVector :: (* -> * -> *) -> (* -> * -> *) -> * -> * -> * where MV :: !(u s a) -> !(v s b) -> MVector u v s (a, b) instance (GMVector u a, GMVector v b) => GMVector (MVector u v) (a, b) where gmbasicLength (MV ks _) = gmbasicLength ks gmbasicUnsafeSlice s e (MV ks vs) = MV (gmbasicUnsafeSlice s e ks) (gmbasicUnsafeSlice s e vs) gmbasicUnsafeNew n = liftM2 MV (gmbasicUnsafeNew n) (gmbasicUnsafeNew n) -- Removing this INLINE pragma makes it compile {-# INLINE gmbasicUnsafeNew #-} gmbasicUnsafeWrite (MV ks vs) n (k,v) = do gmbasicUnsafeWrite ks n k gmbasicUnsafeWrite vs n v data Vector :: (* -> *) -> (* -> *) -> * -> * type instance GMutable (Vector u v) = MVector (GMutable u) (GMutable v) instance (GVector u a, GVector v b) => GVector (Vector u v) (a, b) where gbasicUnsafeFreeze = undefined instance (GVector u a, GVector v b, Read a, Read b, c ~ (a, b)) => Read (Vector u v c) where readPrec = greadPrec }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * version: 8.1 => 8.0.1 Comment: Oh dear, there's actually a distinction between the attached program and the program in comment:4. The attached program compiles without issue on GHC 8.0.2 and earlier, but panics on GHC HEAD (post–join points). The program in comment:4, however, compiles without issue on GHC 7.10.3 and earlier, but panics on GHC 8.0.1, 8.0.2, //and// HEAD. This isn't terribly surprising, as [https://github.com/ekmett/hybrid- vectors/issues/7#issue-133619382 others have reported] seeing this error on earlier versions of GHC, but AFAICT, no one was able to minimize the panic down to a single file until now. So the issue likely predates join points, but join points have made it easier to trigger in GHC HEAD. I'll see if I can figure out what commit lead to the panic surfacing in the program in comment:4. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints Operating System: Unknown/Multiple | 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 RyanGlScott): Huh, the commit which caused the regression in comment:4 is 6746549772c5cc0ac66c0fce562f297f4d4b80a2 (Add kind equalities to GHC). What this means, I have no idea. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints, | SpecConstr Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * keywords: JoinPoints => JoinPoints, SpecConstr -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints, | SpecConstr Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by George): * cc: goldfire (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: simonpj Type: bug | Status: new Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints, | SpecConstr Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * owner: (none) => simonpj Comment: I know exactly what is happening here. Just starved of time to fix it -- and next week looks little better. In brief: `TyCoRep.substCoVarBndr` is replacing occurrences of the binder with `Refl` in the LHS of a rule. Solution: `mkCoVarCo` should not replace varaibles with `Refl`; but `optCoercion` should do so instead. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule
-------------------------------------+-------------------------------------
Reporter: RyanGlScott | Owner: simonpj
Type: bug | Status: new
Priority: highest | Milestone: 8.2.1
Component: Compiler | Version: 8.0.1
Resolution: | Keywords: JoinPoints,
| SpecConstr
Operating System: Unknown/Multiple | 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 Simon Peyton Jones
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: simonpj Type: bug | Status: merge Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: JoinPoints, | SpecConstr Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | simplCore/should_compile/T13410 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * status: new => merge * testcase: => simplCore/should_compile/T13410 Comment: OK, done! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13410: GHC HEAD regression: Template variable unbound in rewrite rule -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: simonpj Type: bug | Status: closed Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Resolution: fixed | Keywords: JoinPoints, | SpecConstr Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | simplCore/should_compile/T13410 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: Merged to `ghc-8.2` as 7087abfe2ba944d6609eee399c5ad2ca44cd388c. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13410#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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