[QuickCheck] Unxpected compositional behaviour

[Simon Hengel]

Hey Nick,

> The reason this happens is that Property is currently a type synonym
> for Gen Prop - i.e. something which when given a random number seed
> will return a test outcome. In your example you are testing the first
> property and then throwing away the result. Property should really be
> an abstract type to prevent this kind of problem - I've put it on my
> todo list :)

I'd prefer to have it just newtype-wrapped, but not abstract, so that
you can still tinker with it.

(would be fine if you have to import an "Internal" module, or something
to get the constructor, though)

Cheers,
Simon