1const U = union(enum) {
 2    int: isize,
 3    float: f64,
 4};
 5
 6export fn entry() void {
 7    const f = U{ .int = 20 };
 8    _ = f.float();
 9}
10
11// error
12//
13// :8:10: error: access of union field 'float' while field 'int' is active
14// :1:11: note: union declared here