Oh, this is silly. Of course it is: forAllShrink linesGen shrink ... On 15/08/12 20:35, Niklas Hambüchen wrote:

I wrote this Gen to generate lines of texts without \NUL and \n:

fullLinesProp = forAll linesGen ...

linesGen = listOf . listOf $ arbitrary `suchThat` (`notElem` ['\NUL', '\n']) -- alternatively: linesGen = arbitrary `suchThat` (all (all (`notElem` ['\NUL', '\n'])))

However, I just realized that QuickCheck disables shrinking when I use this instead of (linesGen = arbitrary :: Gen [String]).

Why is that? Is there a way to get what I want + shrinking without defining a custom shrink (e.g. forAllShrink)?

Thanks