#14247: Fails to coerce between newtypes directly -------------------------------------+------------------------------------- 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): It's artificial and follows from me discussing "deriving via a `newtype`" with Ryan; we wondered if there could be a way to derive via a regular `data` type.. which lead me to something like {{{#!hs newtype W a = W a data A = MkA (W A) }}} where coercing `coerce :: A -> W A` actually works: make `A` a `newtype` and it stops working. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14247#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler