#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): Replying to [comment:5 goldfire]:
But you should get no warning with `-XAllowAmbiguousTypes`, as that skips the ambiguity check that causes the warning. Or am I mistaken here?
You do get a warning, it seems: {{{ $ /opt/ghc/8.0.1/bin/runghc -Wall -XAllowAmbiguousTypes TheFloatDigits.hs TheFloatDigits.hs:6:19: warning: [-Wtype-defaults] • Defaulting the following constraint to type ‘Double’ RealFloat a0 • In the ambiguity check for ‘theFloatDigits’ In the type signature: theFloatDigits :: forall a. RealFloat a => Int (53,24) }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11947#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler