(Section 28.2)

Says: For p it is Point, whereas for pAnon it is an anonymous class of
Point.

Should say: For p it is Point, whereas for pAnon it is an anonymous
subclass of Point.

FIXED

l.-8 all, Branch[_] is a technically a type
-->  all, Branch[_] is   technically a type

FIXED

advice about taking elements of array into account when calculating hash
code seems to contradict earlier advice about not basing a hash code on
mutables (done indirectly here)

THAT'S A GOOD POINT. MAYBE WORTH A FOOTNOTE. WILL CONSIDER THIS FOR A
FUTURE EDITION.