#11032: Missing result type handling for State# s in foreign import prim. -------------------------------------+------------------------------------- Reporter: ekmett | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (FFI) | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): I see in `TcType` this comment: {{{ Note [Marshalling VoidRep] ~~~~~~~~~~~~~~~~~~~~~~~~~~ We don't treat State# (whose PrimRep is VoidRep) as marshalable. In turn that means you can't write foreign import foo :: Int -> State# RealWorld Reason: the back end falls over with panic "primRepHint:VoidRep"; and there is no compelling reason to permit it }}} I don't think there is any fundamental reason not to allow this. Would someone like to free it up? It'd mean looking at that `ptrRepHint` stuff. Thanks! Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11032#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler