#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 simonpj): For what it's worth, I don't have a strong opinion either way. I think we are agreed that: * In an user-written type signature, * if an application of a closed type family is "apart" from all equations of the family, * then we should signal either an error or a warning. Lennart says "error", Richard says "warning", and I can't work up much excitement about which is chosen. One advantage of "error" is that you don't have to add a flag to suppress the warning! Anyway, if someone wants to implement it, go ahead! This all applies to ''user-written type signatures''. I don't want to apply this to "types that appear during the type inference process" because I don't know exactly what that might mean. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9636#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler