#2431: allow empty case analysis
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Reporter: RalfHinze | Owner:
Type: feature request | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.8.3
Severity: minor | Resolution:
Keywords: empty case analysis | Difficulty: Unknown
Testcase: | Architecture: Unknown
Os: Unknown |
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Changes (by Isaac Dupree):
* cc: [EMAIL PROTECTED] (added)
Comment:
Of course, with the correct warning flags enabled, empty case of a non-
empty type will produce an "incomplete pattern match" warning: exactly
when we want a warning for using this construct.
I suppose the effect is to throw a pattern-match error that is independent
of the case'd value, as consistent with all patterns of any other case
statement failing? (rather than using it if it's _|_, as of course it
will be if it's an empty type: because, unlike in GHC Core, source-Haskell
'case' does not introduce strictness)
+1, I've occasionally wanted this to be possible
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2431#comment:3>
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