#14386: GHC doesn't allow Coercion between partly-saturated type constructors -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 Resolution: | Keywords: roles 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 Iceland_jack): I wondered because we allow {{{#!hs import Data.Type.Coercion newtype USD = USD Int wit :: Coercion (Either USD) (Either Int) wit = Coercion }}} I don't understand Core enough to get the difference, but (prima facie) it doesn't seem wrong to allow `Coercion (Op (Op cat)) cat`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14386#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler