[Haskell-beginners] quickCheck generation question

[Christian Maeder]

Am 08.10.2011 01:40, schrieb Joe Van Dyk:
> I'm going through the 99 Haskell problems and am trying to write
> quickCheck properties for each one.
>
> -- 3 (find k"th element of a list)
> element_at xs x = xs !! x
> prop_3a xs x = (x<  length xs&&  x>= 0) ==>  element_at xs (x::Int) ==
> (xs !! x::Int)

The definition and test look very similar (basically "=" is replaced by 
"=="). So this seems to test reliability of definitions and Eq 
instances. Such tests should not be necessary. (Testing different 
implementations for equality makes more sense.)

Cheers Christian