#14174: GHC panic with TypeInType and type family -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.2 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: | Keywords: TypeInType 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 Iceland_jack): * cc: Iceland_jack (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14174#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#14174: GHC panic with TypeInType and type family -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.3 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: | Keywords: TypeInType 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): * milestone: 8.2.2 => 8.2.3 Comment: It looks like this won't be fixed in 8.2.2. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14174#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#14174: GHC panic with TypeInType and type family -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.3 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: | Keywords: TypeInType 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 ): In [changeset:"8b36ed129652df07af22b5e2a2e57b1df8cfbbc9/ghc" 8b36ed1/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="8b36ed129652df07af22b5e2a2e57b1df8cfbbc9" Build only well-kinded types in type checker During type inference, we maintain the invariant that every type is well-kinded /without/ zonking; and in particular that typeKind does not fail (as it can for ill-kinded types). But TcHsType.tcInferApps was not guaranteeing this invariant, resulting in Trac #14174 and #14520. This patch fixes it, making things better -- but it does /not/ fix the program in Trac #14174 comment:5, which still crashes. So more work to be done. See Note [Ensure well-kinded types] in TcHsType }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14174#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#14174: GHC panic with TypeInType and type family -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.3 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | polykinds/T14174.hs, T14174a Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"0a12d92a8f65d374f9317af2759af2b46267ad5c/ghc" 0a12d92a/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="0a12d92a8f65d374f9317af2759af2b46267ad5c" Further improvements to well-kinded types The typechecker has the invariant that every type should be well-kinded as it stands, without zonking. See Note [The well-kinded type invariant] in TcType. That invariant was not being upheld, which led to Trac #14174. I fixed part of it, but T14174a showed that there was more. This patch finishes the job. * See Note [The tcType invariant] in TcHsType, which articulates an invariant that was very nearly, but not quite, true. One place that falisified it was the HsWildCardTy case of tc_hs_type, so I fixed that. * mkNakedCastTy now makes no attempt to eliminate casts; indeed it cannot lest it break Note [The well-kinded type invariant]. The prior comment suggested that it was crucial for performance but happily it seems not to be. The extra Refls are eliminated by the zonker. * I found I could tidy up TcHsType.instantiateTyN and instantiateTyUntilN by eliminating one of its parameters. That led to a cascade of minor improvements in TcTyClsDecls. Hooray. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14174#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler

#14174: GHC panic with TypeInType and type family -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.2.3 Component: Compiler (Type | Version: 8.2.1 checker) | Resolution: fixed | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Compile-time | Test Case: crash or panic | polykinds/T14174.hs, T14174a Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Simon Peyton Jones ): In [changeset:"3d252037234ce48f9bdada7d5c9b1d8eba470829/ghc" 3d252037/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="3d252037234ce48f9bdada7d5c9b1d8eba470829" Respect Note [The tcType invariant] I tried to do this with commit 0a12d92a8f65d374f9317af2759af2b46267ad5c Author: Simon Peyton Jones Date: Wed Dec 13 12:53:26 2017 +0000 Further improvements to well-kinded types The typechecker has the invariant that every type should be well- kinded as it stands, without zonking. See Note [The well-kinded type invariant] in TcType. That invariant was not being upheld, which led to Trac #14174. I fixed part of it, but T14174a showed that there was more. This patch finishes the job. But I didn't get it quite right as Trac #14873 showed. This patch fixes the problem; although I am still a bit unhappy. (See "A worry" in the HsApp case of tc_infer_hs_type.) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14174#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler