#6018: Injective type families -------------------------------------+------------------------------------- Reporter: lunaris | Owner: jstolarek Type: feature | Status: new request | Milestone: 7.10.1 Priority: normal | Version: 7.4.1 Component: Compiler | Keywords: TypeFamilies, Resolution: | Injective Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: #4259 Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by goldfire): That syntax precludes the possibility of `result` being the name of an argument to the function. Using `Result` avoids this problem, but that would be a capitalized keyword, which is strange. The other possibility that avoids stealing the name `result` is to use the type family itself to represent the result: `type family F a | F -> a`, but that's a little strange. I guess I favor the last syntax the most. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/6018#comment:46 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler