#9636: Function with type error accepted -------------------------------------+------------------------------------- Reporter: augustss | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by augustss): I would like it to apply to types that appear during type checking, because I think it's an error and errors should be reported. I presume that at some point during type checking the closed type family equations are used to simplify a type. If at that point you discover that none of the equations can possibly match, then that should be reported as an error. If irreducible closed type family (type) expressions are allowed then these are some kind of "ghost types". If we agree that that only "data" and "newtype" generate types, then these ghosts are some new kind of types that have no meaning. They are not empty types, they simply malformed. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9636#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler