#16347: GHC HEAD regression: piResultTys1 -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: Component: Compiler (Type | Version: 8.7 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 goldfire): In conversation, Simon and I uncovered an unstated invariant: the `tyVarKind` of occurrences of a bound tyvar must share the `tyVarKind` of the binding site. In this example, that is not the case, because the kind of the tyvar contains a metavariable; it is zonked at an occurrence but not at the binding site. The fix is easy: do an extra zonk in `kcLHsQTyVars_NonCusk`, but fixing #16344 will also make this problem melt away. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16347#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler