On Wednesday 20 April 2011 11:43:08, larry.liuxinyu wrote: > Hi, > > I found there is similar question as: > http://groups.google.com/group/haskell-cafe/browse_thread/thread/7439262 > e9ac80dd2/91ca18e11ff00649?lnk=gst&q=QuickCheck+Ord+a#91ca18e11ff00649 > > I am still think it's very strange. For example: > > prop_foo :: (Ord a) => [a] -> Property > prop_foo xs = not (null xs) ==> maximum xs == minimum xs > > This is an extreme case that the property is always wrong.
Not always, replicate n x has this property. > > However, QuickCheck produces: > *Main> test prop_foo > OK, passed 100 tests. > > This works at least, However, since 'a'<'b', they are order-able, what > if I want to test prop_foo works for char? ghci> test (prop_foo :: [Char] -> Property) You have to determine the type, by an explicit signature or by context. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe