Coercible is a special constraint with custom solving rules. Please see
#12390: List rules for `Coercible` instances -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 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 nomeata): Maybe it would work better if a symbol could have an text field attatched for “arbitrary text to be displayed on `:info`”, and `:info` would show that. It could simply say section ... of the user’s guide for details. Note that we stopped calling `Coercible` a class; as it is not a class. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12390#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler