#12862: Operator (!) causes weird pretty printing and parsing -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs class Key key where data TotalMap key :: Type -> Type (!) :: TotalMap key val -> (key -> val) instance Key Bool where data TotalMap Bool val = BoolMap val val (!) :: TotalMap Bool val -> (Bool -> val) (BoolMap f _) ! False = f }}} puts unnecessary parentheses around the wildcard pattern: {{{ tf6t.hs:14:3-23: error: … Parse error in pattern: (BoolMap f (_)) Compilation failed. }}} and with no parentheses {{{#!hs BoolMap f _ ! False = f }}} it talks about missing method, pattern bindings and doesn't list a space between `!` and `False`: {{{ tf6t.hs:13:3-5: error: … The class method signature for ‘!’ lacks an accompanying binding (The class method signature must be given where ‘!’ is declared) tf6t.hs:14:3-25: error: … Pattern bindings (except simple variables) not allowed in instance declaration: BoolMap f _ !False = f Compilation failed. }}} All of these issues go away if the operator is called something other than `!`, it works if written prefix {{{#!hs (!) (BoolMap f _) False = f }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12862 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler