#12709: GHC panic -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: | LevityPolymorphism Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Richard Eisenberg <rae@…>): In [changeset:"dca44adb9e14992e0aed49cdfd4b2baa2182073b/ghc" dca44adb/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="dca44adb9e14992e0aed49cdfd4b2baa2182073b" Fix #12709 by not building bad applications In an effort to report multiple levity polymorphism errors all at once, the desugarer does not fail when encountering bad levity polymorphism. But we must be careful not to build the bad applications, lest they try to satisfy the let/app invariant and call isUnliftedType on a levity polymorphic type. This protects calls to mkCoreAppDs appropriately. test case: typecheck/should_fail/T12709 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12709#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler