#10018: Cannot define custom fixity for infix data constructors in GHCi -------------------------------------+------------------------------------- Reporter: | Owner: RyanGlScott | Status: new Type: bug | Milestone: Priority: normal | Version: 7.8.4 Component: GHCi | Operating System: Unknown/Multiple Keywords: | Type of failure: Incorrect result Architecture: | at runtime Unknown/Multiple | Blocked By: Test Case: | Related Tickets: Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- When compiling from a module, declaring a custom fixity for an infix data constructor is valid: {{{#!hs module DataFixity where data Infix a b = a :@: b infixl 4 :@: }}} And GHCi recognizes this: {{{ $ ghci DataFixity.hs GHCi, version 7.8.4: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling DataFixity ( DataFixity.hs, interpreted ) Ok, modules loaded: DataFixity. λ> :i :@: data Infix a b = a :@: b -- Defined at DataFixity.hs:3:18 infixl 4 :@: }}} However, one cannot do this entirely in GHCi: {{{ $ ghci GHCi, version 7.8.4: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. λ> data Infix a b = a :@: b; infixl 4 :@: λ> :i (:@:) data Infix a b = a :@: b -- Defined at <interactive>:2:18 }}} GHCi simply assumes {{{:@:}}} has the default infix precedence. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10018 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler