#14765: Levity polymorphism panic -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.5 Resolution: | Keywords: | LevityPolymorphism 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 simonpj): More thoughts
Perhaps we could just make that more efficient by not using tryM.
I really don't like having isUnliftedType return False for levity
No: we need to know if there are any error messages ''from the enclosed thing''. polymorphism. Actually I've decided I do! The compiler should panic if there is no other alternative. Here there is -- and Lint will catch the error shortly afterwards in a much more civilised way. It's such a simple fix.
How would the new mkCoreApp work?
Just like the current one, but without panicing in `isUnliftedType`, and with the entire apparatus introduced by #12709. That is, build a term that may not pass Lint; but it doesn't matter because we are going to report LP errors anyway and stop. So a "new mkCoreApp" duplicates code, but in exchange means that all other uses of `isUnliftedType` can panic if you still feel strongly that they should. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14765#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler