Question

I’ve come across this error a few times. It’s pretty self explanatory, the mismatch is coming on my ans var that is an Int, as I believe it should be, however it’s wanting type prop. I have a feeling it’s syntax related, the way I’m constructing this, but let me know what you think:

Answer 1

The signature of the implication operator is:

def ==>(p: ⇒ Prop): Prop 

Assuming implicit conversions are in scope, it should be possible to construct a Prop from a Boolean. Therefore, you only need brackets around (ans == n*m). Otherwise the argument to ==> will just be ans, i.e. an Int, which cannot be converted to Prop.

The required implicit conversion is:

 implicit def propBoolean(b: Boolean): Prop

and is in object Prop, so ensure to import org.scalacheck.Prop.propBoolean.