#10056: Inconsistent precedence of ~ -------------------------------------+------------------------------------- Reporter: crockeea | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 (Parser) | Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: #10059 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by RyanGlScott): OK, so the idea is to still require that user-defined fixity declarations have precedence 0–9, but grant exceptions for certain types (e.g., `(~)`). I think this would technically meet the Haskell 2010 Report, so that's good. As far as implementation details go, it looks like `(->)`'s fixity is currently hardwired in [http://git.haskell.org/ghc.git/blob/f063bd5413edf40f1b48e0f958410dcb6bf20b68... BasicTypes.hs], so we could stick in {{{tildeFixity = Fixity (-1) Infix}}} there. I'm not aware of any bounds-checking code that would be tripped up by having a precedence lower than {{{minPrecedence = 0}}}, so I don't think that would be too invasive of a change. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10056#comment:23 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler