structural type Foo0 = Foo0
structural type Foo1 a = Foo1 a
structural type Foo2 a b = Foo2 a b
structural type Foo3 a b c = Foo3 a b c

use Foo0 Foo0
use Foo1 Foo1
use Foo2 Foo2

x = match Foo0 with
  Foo0 -> 1

y = match Foo1 1 with
  Foo1 1 -> 0
  Foo1 _ -> 10

z = match Foo2 1 "hi" with
  Foo2 1 "hi" -> 1
  Foo2 x "bye" -> x
  _ -> bug "unexpected"

> z