
#12980: Unlifted class method rejected -------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- If I say {{{#!hs class C a where meth :: Array# a }}} I get {{{ • Expecting a lifted type, but ‘Array# a’ is unlifted • In the type signature: meth :: Array# a In the class declaration for ‘C’ }}} This definition looks OK to me. I don't see why we can't have an unlifted member of a class. (As @oerjan points out in comment:25:ticket:12708, we can't have a ''levity-polymorphic'' class member, but this is solidly levity- monomorphic.) I'm happy to lift this restriction in ongoing work in this area, but I wanted to double-check before doing so. For the record, the same error occurs even when the class has more than one member, so it's not the no-unlifted-newtypes restriction. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12980 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler