#10018: Cannot define custom fixity for infix data constructors in GHCi -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 7.10.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by RyanGlScott): * status: closed => new * version: 7.8.4 => 7.10.1-rc2 * resolution: fixed => Comment: Sorry, it turns out that the bug is more nuanced than I thought. I prematurely closed this ticket when I discovered that a {{{deriving Show}}} clause does in fact pick up on a custom fixity: {{{ $ ghci GHCi, version 7.10.0.20150123: http://www.haskell.org/ghc/ :? for help λ> data Infix a b = a :@: b deriving Show; infix 4 :@: λ> showsPrec 4 ('a' :@: 'b') "" "'a' :@: 'b'" λ> showsPrec 5 ('a' :@: 'b') "" "('a' :@: 'b')" }}} So as far as {{{Show}}} is concerned, {{{:@:}}} is {{{infix 4}}}. However, it behaves as {{{infixl 11}}} when it is actually used: {{{ λ> 'a' :@: 'b' :@: 'c' ('a' :@: 'b') :@: 'c' }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10018#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler