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

   1 #![warn(explicit_write)]
   2
   3
   4 fn stdout() -> String {
   5     String::new()
   6 }
   7
   8 fn stderr() -> String {
   9     String::new()
  10 }
  11
  12 fn main() {
  13     // these should warn
  14     {
  15         use std::io::Write;
  16         write!(std::io::stdout(), "test").unwrap();
  17         write!(std::io::stderr(), "test").unwrap();
  18         writeln!(std::io::stdout(), "test").unwrap();
  19         writeln!(std::io::stderr(), "test").unwrap();
  20         std::io::stdout().write_fmt(format_args!("test")).unwrap();
  21         std::io::stderr().write_fmt(format_args!("test")).unwrap();
  22     }
  23     // these should not warn, different destination
  24     {
  25         use std::fmt::Write;
  26         let mut s = String::new();
  27         write!(s, "test").unwrap();
  28         write!(s, "test").unwrap();
  29         writeln!(s, "test").unwrap();
  30         writeln!(s, "test").unwrap();
  31         s.write_fmt(format_args!("test")).unwrap();
  32         s.write_fmt(format_args!("test")).unwrap();
  33         write!(stdout(), "test").unwrap();
  34         write!(stderr(), "test").unwrap();
  35         writeln!(stdout(), "test").unwrap();
  36         writeln!(stderr(), "test").unwrap();
  37         stdout().write_fmt(format_args!("test")).unwrap();
  38         stderr().write_fmt(format_args!("test")).unwrap();
  39     }
  40     // these should not warn, no unwrap
  41     {
  42         use std::io::Write;
  43         std::io::stdout().write_fmt(format_args!("test")).expect("no stdout");
  44         std::io::stderr().write_fmt(format_args!("test")).expect("no stderr");
  45     }
  46 }