#7102: Type family instance overlap accepted in ghci -------------------------------------+------------------------------------- Reporter: exbb2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC accepts | Unknown/Multiple invalid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by oerjan): * cc: oerjan (added) * status: closed => new * resolution: wontfix => Comment: I think this behavior should be reconsidered when Safe Haskell is enabled. {{{ Prelude> :set -XSafe Prelude> :seti -XSafe Prelude> :set -XTypeFamilies Prelude> type family T a b Prelude> type instance T a b = a Prelude> let fro :: a -> T a b; fro = id Prelude> type instance T a b = b Prelude> let uc :: a -> b; uc = fro Prelude> uc 'a' :: Int 97 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7102#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler