constraints Package

The golang.org/x/exp/constraints package ships a small set of named type constraints (Ordered, Integer, Float, Signed, Unsigned, Complex) that almost every generic Go function ends up needing. Instead of hand-rolling a type Number interface { ~int | ~int8 | ... } in every file, you import the package and use what's already there. This chapter covers what each constraint actually contains, how to compose them, why the package still lives under x/exp, and how Go 1.21's stdlib cmp.Ordered together with the slices and maps packages changes the picture.