#13149: Giving Backpack a Promotion -------------------------------------+------------------------------------- Reporter: ezyang | Owner: Type: task | Status: new Priority: normal | Milestone: Research Component: Compiler (Type | needed checker) | Version: 8.1 Resolution: | Keywords: backpack 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): Yes, with `-XTypeInType`, coercions appear in types. For example: {{{ type family F a where F Bool = Type foo :: forall (a :: F Bool). a -> a foo x = x }}} (Panics in GHC 8.0.1, but works in HEAD.) The type of `foo` will contain a reference to a coercion axiom. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13149#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler