#5910: Holes with other constraints ----------------------------------------+----------------------------------- Reporter: xnyhps | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type checker) | Version: 7.5 Keywords: holes | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: Incorrect warning at compile-time Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ----------------------------------------+-----------------------------------
Comment(by spl): It seems to me that ambiguous types are the key problem here. We've been working on this a bit at UHac, but we haven't yet reached a solution. Thijs has already mentioned the problem with: {{{ show _?x }}} Paolo has also pointed out the following: {{{ data Foo a = Foo a data Bar1 = Bar1 data Bar2 = Bar2 instance Show (Foo Bar1) where instance Show (Foo Bar2) where test = show (Foo _?y) }}} What type do we get for the type of {{{_?y}}}? It appears unknowable. Perhaps we can solve only part of the problem. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5910#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs