#12363: Type application for infix -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 8.0.1 (Parser) | Keywords: Resolution: | TypeApplications Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by goldfire): Replying to [comment:18 rwbarton]:
I know the manual says you can write things like `f x @Bool` meaning `(f x) @Bool` if `f` has a suitable type, though I wonder if there are any real uses for that.
One plausible-sounding scenario is in specializing a polymorphic function accessed by a record selector: {{{#!hs data Mon'd m = MkMon'd { ret'rn :: forall a. a -> m a } f :: Mon'd m -> ... f dict ... = ... ret'rn dict @Int ... }}} But, yes, frequently the function applied to type parameters is just an identifier. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12363#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler