1 #![allow(unused_must_use)]
2 #![warn(clippy::write_literal)]
3
4 use std::io::Write;
5
main()6 fn main() {
7 let mut v = Vec::new();
8
9 // these should be fine
10 write!(&mut v, "Hello");
11 writeln!(&mut v, "Hello");
12 let world = "world";
13 writeln!(&mut v, "Hello {}", world);
14 writeln!(&mut v, "Hello {world}", world = world);
15 writeln!(&mut v, "3 in hex is {:X}", 3);
16 writeln!(&mut v, "2 + 1 = {:.4}", 3);
17 writeln!(&mut v, "2 + 1 = {:5.4}", 3);
18 writeln!(&mut v, "Debug test {:?}", "hello, world");
19 writeln!(&mut v, "{0:8} {1:>8}", "hello", "world");
20 writeln!(&mut v, "{1:8} {0:>8}", "hello", "world");
21 writeln!(&mut v, "{foo:8} {bar:>8}", foo = "hello", bar = "world");
22 writeln!(&mut v, "{bar:8} {foo:>8}", foo = "hello", bar = "world");
23 writeln!(&mut v, "{number:>width$}", number = 1, width = 6);
24 writeln!(&mut v, "{number:>0width$}", number = 1, width = 6);
25 writeln!(&mut v, "{} of {:b} people know binary, the other half doesn't", 1, 2);
26 writeln!(&mut v, "10 / 4 is {}", 2.5);
27 writeln!(&mut v, "2 + 1 = {}", 3);
28
29 // these should throw warnings
30 write!(&mut v, "Hello {}", "world");
31 writeln!(&mut v, "Hello {} {}", world, "world");
32 writeln!(&mut v, "Hello {}", "world");
33
34 // positional args don't change the fact
35 // that we're using a literal -- this should
36 // throw a warning
37 writeln!(&mut v, "{0} {1}", "hello", "world");
38 writeln!(&mut v, "{1} {0}", "hello", "world");
39
40 // named args shouldn't change anything either
41 writeln!(&mut v, "{foo} {bar}", foo = "hello", bar = "world");
42 writeln!(&mut v, "{bar} {foo}", foo = "hello", bar = "world");
43 }
44