if y.Kind() != abi.Func {
		return false
	}
	yield := y.FuncType()
	return yield.InCount == 2 && yield.OutCount == 1 && yield.Out(0).Kind() == abi.Bool
}

// add returns p+x.
//
// The whySafe string is ignored, so that the function still inlines
// as efficiently as p+x, but all call sites should use the string to
// record why the addition is safe, which is to say why the addition