#14547: Wrong warning by -Wincomplete-patterns -------------------------------------+------------------------------------- Reporter: YoshikuniJujo | Owner: (none) Type: bug | Status: patch Priority: low | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: incomplete- | patterns OverloadedLists, | PatternMatchWarnings TypeFamilies Operating System: Linux | Architecture: x86 Type of failure: Incorrect | Test Case: error/warning at compile-time | deSugar/should_compile/T14547 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D4624 Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj):
Indeed we don't need to know the toList of [] instance is identity function,
Good point. So this ticket is * not about overloaded strings * not about type functions It's only about view patterns. Could you re-formulate the example to eliminate the unnecessary clutter, and focus just on view patterns? And then (sorry to be slow) take us more slowly through what the problem is? It'll be something to do with the way that the pattern match checker deals with view patterns, I guess. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14547#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler