Re: [GHC] #14174: GHC panic with TypeInType and type family

#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