#13537: Adding underscore (m :: _) to pattern variable makes it fail -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler (Type | Version: 8.0.1 checker) | Resolution: invalid | 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 simonpj):
To be clear, this is also expected?
Yes, but for an entirely different reason. The local binding `g' = g` is not generalised, because with `GADTs` on (which you presumably have) we have `MonoLocalBinds` on too. So `g'` is no generalised; and hence it's rejected as an argumen to `MkT`. If you gave `g'` a type signature you'd be fine. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13537#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler