src/tools/clippy/tests/ui/write_literal.rs

   1 #![allow(unused_must_use)]
   2 #![warn(clippy::write_literal)]
   3
   4 use std::io::Write;
   5
   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 }