1comptime {
 2    blk: {
 3        blk: while (false) {}
 4    }
 5}
 6comptime {
 7    blk: while (false) {
 8        blk: for (@as([0]void, undefined)) |_| {}
 9    }
10}
11comptime {
12    blk: for (@as([0]void, undefined)) |_| {
13        blk: {}
14    }
15}
16comptime {
17    blk: {}
18}
19comptime {
20    blk: while (false) {}
21}
22comptime {
23    blk: for (@as([0]void, undefined)) |_| {}
24}
25comptime {
26    blk: switch (true) {
27        else => {},
28    }
29}
30
31// error
32//
33// :3:9: error: redefinition of label 'blk'
34// :2:5: note: previous definition here
35// :8:9: error: redefinition of label 'blk'
36// :7:5: note: previous definition here
37// :13:9: error: redefinition of label 'blk'
38// :12:5: note: previous definition here
39// :17:5: error: unused block label
40// :20:5: error: unused while loop label
41// :23:5: error: unused for loop label
42// :26:5: error: unused switch label