#13680: Can't use TypeApplications with [] data constructor -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) 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: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * cc: mpickering (added) Comment: Huh, I certainly didn't realize that lists were unique in this regard. In fact, the warning even goes away if you replace `[]` with an empty string literal! {{{ λ> case [] of (_:_) -> case () of a -> undefined <interactive>:5:12: warning: [-Woverlapping-patterns] Pattern match is redundant In a case alternative: (_ : _) -> ... *** Exception: <interactive>:5:1-45: Non-exhaustive patterns in case λ> case "" of (_:_) -> case () of a -> undefined *** Exception: <interactive>:6:1-45: Non-exhaustive patterns in case }}} In that case, I'm slightly more comfortable with making this change. But just in case, I'll cc mpickering, the author of the `T12957` test, to make sure he's comfortable with this idea. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13680#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler