#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 <simonpj@…>): 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