#14500: Coercion artifact ‘cobox’ appears in error message -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 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 Iceland_jack): More output: Replacing it with {{{#!hs pattern SO <- Bloop' (HRefl::N:~~:kk) (typeRep :: TypeRep O) }}} gives {{{ /tmp/Bug.hs:14:40: error: • Could not deduce: a ~ ('O |> Sym cobox) from the context: (* ~ *, kk ~ N) bound by a pattern with constructor: HRefl :: forall k1 (a :: k1). a :~~: a, in a pattern synonym declaration at /tmp/Bug.hs:14:23-27 ‘a’ is a rigid type variable bound by the signature for pattern synonym ‘SO’ at /tmp/Bug.hs:13:23 Expected type: TypeRep a Actual type: TypeRep 'O • When checking that the pattern signature: TypeRep 'O fits the type of its context: TypeRep a In the pattern: typeRep :: TypeRep O In the pattern: Bloop' (HRefl :: N :~~: kk) (typeRep :: TypeRep O) | 14 | pattern SO <- Bloop' (HRefl::N:~~:kk) (typeRep::TypeRep O) | ^^^^^^^^^^^^^^^^^^ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14500#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler