#14112: bang patterns on pattern synonyms? (left vs right hand sides) -------------------------------------+------------------------------------- Reporter: carter | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- I'm trying to define my own fancy strict maybe types, and so i've written some pattern synonyms to wrap them up. imagine my surprise when i find i can write bang patterns on the *right* hand side, but not the left hand! {{{ data MyMaybe a = JustC a | NothingC pattern MyJust :: a -> MyMaybe a -- pattern MyJust !a = JustC a -- this fails pattern MyJust a = JustC !a -- this is fine }}} is this deliberate or a leakage of how desugaring works? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14112 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler