0(1) element: null
1(2) element: PyMatchStatement
2(3,16) refutable pattern: [42] | foo.bar as x
3(4,16) refutable pattern: [42] | foo.bar
4(5,8) refutable pattern: [42]
5(6,8) refutable pattern: 42
6(7) matched pattern: 42
7(12) matched pattern: [42]
8(9,16) refutable pattern: foo.bar
9(10) READ ACCESS: foo
10(11) matched pattern: foo.bar
11(12) matched pattern: [42] | foo.bar
12(13) WRITE ACCESS: x
13(14) matched pattern: [42] | foo.bar as x
14(15) element: PyExpressionStatement
15(16) READ ACCESS: y
16(17) element: PyExpressionStatement
17(18) READ ACCESS: z
18() element: null