#10653: PatternSynonyms should be imported/exported as part of the wildcard notation -------------------------------------+------------------------------------- Reporter: gridaphobe | Owner: mpickering Type: feature request | Status: new Priority: high | Milestone: 8.0.1 Component: Compiler | Version: 7.11 Resolution: | Keywords: | PatternSynonyms, pattern synonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonpj): I just want to check that you really intend this to work {{{ module M( Maybe(P) ) where pattern P x y = (x, True, y) module N( T(P, X, Y) ) where import M( Maybe(..) ) data T = X | Y }}} Pattern synonym `P` has ''absolutely nothing'' to do with the `Maybe`, but as I understand it module `M` is legal under this proposal, and anyone going `import M( Maybe(..) )` will get `P` in scope. Then module `N` gets the `P` from the import, and attaches it to the also- unrelated data type `T`. I think it's all well-defined, but perhaps rather surprising. Is there a consensus that this is the behaviour we all want; or has it perhaps simply not been discussed? A possible restriction might be that you can only add `P` to an export of a data type `T` if `P`'s type has form `... -> T t1 ..tn`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10653#comment:30 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler