#8778: Typeable TypeNats --------------------------------------------+------------------------------ Reporter: dmcclean | Owner: Type: feature request | Status: new Priority: normal | Milestone: ⊥ Component: Compiler (Type checker) | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: 4385 --------------------------------------------+------------------------------ Comment (by diatchki): Aha, thanks for the Phabricator tip! I redid the instances to be of the form `\_ -> blah`. About the `Typeable` instance: in normal modules we only allow machine- generated instances. The module `Data.Typeable.Internal` is an exception though---it allows manual instances to accommodate custom instances for some types. One note about the type-literal instances: they have a much higher chance of collision than a typical kind, as both `Nat` and `Symbol` have infinitely many type-constructors, which need to fit into the fingerprint. I am not sure how much of a realistic problem this is, but it is something to keep in mind. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8778#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler