#10746: No non-exhaustive pattern match warning given for empty case analysis -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: | PatternMatchWarnings Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: #7669, #11806 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): I don't think you need to go that far to satisfy many people, although maybe I'm missing something. We mostly want you to inspect all constructors of the relevant datatype that have not obviously been eliminated previously and check that their result types are apart from the type of the scrutinee. The reason for the perhaps-counterintuitive design choice is that a ''lazy'' empty `case` would be quite useless--you'd always be better off with an `error` call than such a beast! Strict empty case, on the other hand, will be quite useful once this bug is squashed. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10746#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler