#11947: GHC mistakenly warns about type defaulting in the presence of -XTypeApplications -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.0.1 checker) | Keywords: Resolution: | TypeApplications Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I suppose this is correct, but it hardly feels intuitive to me. The definition of `theFloatDigits`, as written above, doesn't seem ambiguous at all, given that we are explicitly applying the type `a` to `undefined`. The fact that GHC is emitting a warning at all appears to be byproduct of the particular implementation it uses to check for ambiguity. That being said, it looks like option 2 would be the most sensible option? I can't envision a scenario in which not defaulting types in an ambiguity check would make a difference. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11947#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler