#11103: DuplicateRecordFields + TemplateHaskell -------------------------------------+------------------------------------- Reporter: adamgundry | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Template | Version: 7.11 Haskell | 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: -------------------------------------+------------------------------------- The [wiki:Records/OverloadedRecordFields/DuplicateRecordFields DuplicateRecordFields] extension works by mangling the Names of field selector functions, and treating fields specially in the renamer. Thus if you define {{{ data T = MkT { foo :: Int } }}} then GHC will actually generate a selector called `$sel:foo:MkT`, but will resolve `foo` to refer to this selector. In general we want this name-mangling to be internal only, but at the moment it is visible when using Template Haskell, because the TH AST doesn't have a way to represent the distinction between the selector name and the field label. For example, if you reify `''T` above and then pretty-print it you will currently get {{{ data T = MkT { $sel:foo:MkT :: Int } }}} which is obviously bad. I'm not sure how best to address this. We could represent the name as `mkNameG_v pkg mod "foo"`, which will look okay when inspected, but if it is subsequently reified it might be ambiguous. Should we add a new `NameFlavour`? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11103 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler