[GHC] #15692: GHC panic from pattern synonyms + deferred type errors
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Keywords: | Operating System: Unknown/Multiple PatternSynonyms, TypeInType | Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs {-# Language DataKinds, TypeOperators, PolyKinds, PatternSynonyms, GADTs #-} {-# Options_GHC -dcore-lint -fdefer-type-errors #-} import Data.Kind data Ctx :: Type -> Type where E :: Ctx(Type) (:&:) :: a -> Ctx(as) -> Ctx(a -> as) data ApplyT (k::Type) :: k -> Ctx(k) -> Type where AO :: a -> ApplyT(Type) a E AS :: ApplyT(ks) (f a) ctx -> ApplyT(k -> ks) f (a:&:ctx) pattern ASSO = AS (AS (AO False)) }}} {{{ $ ghci -ignore-dot-ghci 463.hs hs/463.hs:16:27: warning: [-Wdeferred-type-errors] • Couldn't match type ‘a a1 a2’ with ‘Bool’ Expected type: a3 Actual type: Bool • In the pattern: False In the pattern: AO False In the pattern: AS (AO False) | 16 | pattern ASSO = AS (AS (AO False)) | ^^^^^ ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.7.20180828 for x86_64-unknown-linux): urk! lookup local fingerprint $mASSO [iESflb :-> ($trModule, 1ca40dc83a9c879effdb760462cc9a2d), iESgKD :-> ($tc'E, 79f67a27a14dc1bb6eecb39e4b061e2c), iESgKF :-> ($tc':&:, 24793c0c1652ffcf92e04f47d38fa075), iESgKH :-> ($tcCtx, a3f9358cbfe161bf59e75500d70ce0ae), iESgKI :-> ($tc'AO, 72111d1891cb082e989c20a2191a8b4b), iESgKK :-> ($tc'AS, ff019c04c400d5fbdd46ff8a816d4913), iESgKM :-> ($tcApplyT, cbfe28374b4115925c7213e6330ab115)] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable pprPanic, called at compiler/iface/MkIface.hs:524:37 in ghc:MkIface Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternSynonyms 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: PatternSynonyms, TypeInType => PatternSynonyms Comment: Here's a version which doesn't require any `TypeInType` voodoo: {{{#!hs {-# LANGUAGE GADTs #-} {-# LANGUAGE PatternSynonyms #-} {-# OPTIONS_GHC -fdefer-type-errors #-} module Bug where data F x where FS :: F (f a) -> F a pattern FS' = FS False }}} {{{ $ /opt/ghc/8.6.1/bin/ghc Bug.hs [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) Bug.hs:9:18: warning: [-Wdeferred-type-errors] • Couldn't match expected type ‘F (f x)’ with actual type ‘Bool’ • In the pattern: False In the pattern: FS False In the declaration for pattern synonym ‘FS'’ | 9 | pattern FS' = FS False | ^^^^^ ghc: panic! (the 'impossible' happened) (GHC version 8.6.1 for x86_64-unknown-linux): urk! lookup local fingerprint $mFS' [iESfI6 :-> ($trModule, 550028d00664444fecdab255e6368e70), iESgIq :-> ($tc'FS, a6b7c6b435bb17f938e26b19c786b9e3), iESgIs :-> ($tcF, 59ff366e0583120727f8be6ecf210589)] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable pprPanic, called at compiler/iface/MkIface.hs:524:37 in ghc:MkIface }}} This is a regression from GHC 8.4.3: {{{ $ /opt/ghc/8.4.3/bin/ghci Bug.hs GHCi, version 8.4.3: http://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /home/rgscott/.ghci [1 of 1] Compiling Bug ( Bug.hs, interpreted ) Bug.hs:9:18: warning: [-Wdeferred-type-errors] • Couldn't match expected type ‘F (f x)’ with actual type ‘Bool’ • In the pattern: False In the pattern: FS False In the declaration for pattern synonym ‘FS'’ | 9 | pattern FS' = FS False | ^^^^^ Bug.hs:9:18: warning: [-Wdeferred-type-errors] • Couldn't match expected type ‘F (f0 x)’ with actual type ‘Bool’ • In the first argument of ‘FS’, namely ‘False’ In the expression: FS False In an equation for ‘FS'’: FS' = FS False • Relevant bindings include $bFS' :: F x (bound at Bug.hs:9:9) | 9 | pattern FS' = FS False | ^^^^^ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternSynonyms 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): * cc: simonpj (added) Comment: Somewhat ironically, commit 149d7912eb84a24861b021c13d2ee61b44de5856 (`Fix error recovery for pattern synonyms`) introduced this. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors
-------------------------------------+-------------------------------------
Reporter: Iceland_jack | Owner: (none)
Type: bug | Status: new
Priority: normal | Milestone: 8.6.1
Component: Compiler | Version: 8.6.1
Resolution: | Keywords:
| PatternSynonyms
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
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: merge Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | patsyn/should_fail/T15692 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by simonpj): * status: new => merge * testcase: => patsyn/should_fail/T15692 Comment: Thanks. This fix could probably be merged. It modifies a bit more code than I'd usually like in a patch-release, but I'm pretty confident. And it validates of course. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: merge Priority: normal | Milestone: 8.6.2 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | patsyn/should_fail/T15692 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * milestone: 8.6.1 => 8.6.2 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: merge Priority: normal | Milestone: 8.6.2 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | patsyn/should_fail/T15692 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): Is this the same issue? {{{#!hs {-# Language DataKinds, PatternSynonyms, KindSignatures, GADTs #-} {-# Options_GHC -fdefer-type-errors #-} import Data.Kind data N = O | S N data Fin :: N -> Type where FinO :: Fin (S n) data Exists :: (Type -> Type) -> Type where Exists :: f xx -> Exists f pattern O' = Exists FinO }}} {{{ $ ghci -ignore-dot-ghci hs/486.hs GHCi, version 8.7.20180828: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( hs/486.hs, interpreted ) hs/486.hs:15:21: warning: [-Wdeferred-type-errors] • Couldn't match kind ‘*’ with ‘N’ When matching types a :: * -> * Fin :: N -> * Expected type: a xx Actual type: Fin a0 • In the pattern: FinO In the pattern: Exists FinO In the declaration for pattern synonym ‘O'’ | 15 | pattern O' = Exists FinO | ^^^^ ghc-stage2: panic! (the 'impossible' happened) (GHC version 8.7.20180828 for x86_64-unknown-linux): urk! lookup local fingerprint $mO' [iESflb :-> ($trModule, 1ca40dc83a9c879effdb760462cc9a2d), iESgex :-> ($tc'O, 111d9d0cf0cb57db9c77a4d216344e54), iESgKA :-> ($tc'S, 2d7f65aefd4d8c7deac332c17204e2c9), iESgKC :-> ($tcN, 04f8b57a4955bc680fd71fe4cee31a00), iESgKD :-> ($tc'FinO, a20e4215870bd6fb39afb23de637e84a), iESgKF :-> ($tcFin, 8a38d4451422cc87d0cc0459132dad73), iESgKG :-> ($tc'Exists, 365c3f6bd1b8c9580d1ae883b83c2c68), iESgKI :-> ($tcExists, 11a84f66f5d99fe1d3547c0ad0f538ae)] Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in ghc:Outputable pprPanic, called at compiler/iface/MkIface.hs:524:37 in ghc:MkIface Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: merge Priority: normal | Milestone: 8.6.2 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | patsyn/should_fail/T15692 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Replying to [comment:6 Iceland_jack]:
Is this the same issue?
Yes. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#15692: GHC panic from pattern synonyms + deferred type errors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.6.2 Component: Compiler | Version: 8.6.1 Resolution: fixed | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | patsyn/should_fail/T15692 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by bgamari): * status: merge => closed * resolution: => fixed Comment: Merged with 3e050064511ce67ee9150d51cb9db487187be39e. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15692#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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