#11011: Add type-indexed type representations (`TypeRep a`) -------------------------------------+------------------------------------- Reporter: bjmprice | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): I think that `unsafeCoerce` is quite bad and does threaten safety of the whole system, because you can always unpack a `TypeRep` from a `TypeRepX`. But I think I may have an answer -- I have written a very partial `Read` instance in a similar setup [https://github.com/goldfirere/dependent- db/blob/master/Basics.hs here] (used to implement my job talk). That indexed `TypeRepX` by a constraint, but I don't think you need that to get this done. A big difference between my approach and the real one will be that the real one must be open (allow datatype definitions), while my setup is closed. I don't think this is so terrible, though, as we can use a class (somewhat like my `TyConAble`) that provides the ability to read in a tycon. This class could be internal, perhaps protected by a name that can't be written in Haskell. Does this get you unstuck or have I done something silly? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11011#comment:27 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler