#10094: Template Haskell cannot represent type wildcards -------------------------------------+------------------------------------- Reporter: adamgundry | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.10.1-rc1 Component: Template | Operating System: Unknown/Multiple Haskell | Type of failure: GHC rejects Keywords: | valid program Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- There does not appear to be a way for Template Haskell code to generate partial type signature wildcards. The type quasiquote `[t|_|]` results in `Wildcard not allowed`, and use in an expression quasiquote like `[|() :: _|]` results in `Exotic form of type not (yet) handled by Template Haskell _`. It would be useful if TH code could partially constrain the type of the expressions it was generating, without needing to determine the type completely. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10094 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler