#13458: Panic with unsafeCoerce and -dcore-lint -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler (Type | Version: 8.1 checker) | Resolution: | Keywords: 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 dfeuer): One thought: we currently have a rule that no variable can have a levity- polymorphic type, but that doesn't seem quite strong enough in the presence of `unsafeCoerce`. One option might be to decree that a levity- polymorphic type can't occur in negative position in the signature of a binding. That is, I think we should likely reject the ''signature'' of `unsafeCoerce'` altogether. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13458#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler