| // run-rustfix |
| |
| #![allow(clippy::print_literal, clippy::redundant_clone, clippy::to_string_in_format_args)] |
| #![warn(clippy::useless_format)] |
| |
| struct Foo(pub String); |
| |
| macro_rules! foo { |
| ($($t:tt)*) => (Foo(format!($($t)*))) |
| } |
| |
| fn main() { |
| "foo".to_string(); |
| "{}".to_string(); |
| "{} abc {}".to_string(); |
| r##"foo {} |
| " bar"##.to_string(); |
| |
| let _ = String::new(); |
| |
| "foo".to_string(); |
| format!("{:?}", "foo"); // Don't warn about `Debug`. |
| format!("{:8}", "foo"); |
| format!("{:width$}", "foo", width = 8); |
| "foo".to_string(); // Warn when the format makes no difference. |
| "foo".to_string(); // Warn when the format makes no difference. |
| format!("foo {}", "bar"); |
| format!("{} bar", "foo"); |
| |
| let arg: String = "".to_owned(); |
| arg.to_string(); |
| format!("{:?}", arg); // Don't warn about debug. |
| format!("{:8}", arg); |
| format!("{:width$}", arg, width = 8); |
| arg.to_string(); // Warn when the format makes no difference. |
| arg.to_string(); // Warn when the format makes no difference. |
| format!("foo {}", arg); |
| format!("{} bar", arg); |
| |
| // We don’t want to warn for non-string args; see issue #697. |
| format!("{}", 42); |
| format!("{:?}", 42); |
| format!("{:+}", 42); |
| format!("foo {}", 42); |
| format!("{} bar", 42); |
| |
| // We only want to warn about `format!` itself. |
| println!("foo"); |
| println!("{}", "foo"); |
| println!("foo {}", "foo"); |
| println!("{}", 42); |
| println!("foo {}", 42); |
| |
| // A `format!` inside a macro should not trigger a warning. |
| foo!("should not warn"); |
| |
| // Precision on string means slicing without panicking on size. |
| format!("{:.1}", "foo"); // Could be `"foo"[..1]` |
| format!("{:.10}", "foo"); // Could not be `"foo"[..10]` |
| format!("{:.prec$}", "foo", prec = 1); |
| format!("{:.prec$}", "foo", prec = 10); |
| |
| 42.to_string(); |
| let x = std::path::PathBuf::from("/bar/foo/qux"); |
| x.display().to_string(); |
| |
| // False positive |
| let a = "foo".to_string(); |
| let _ = Some(a + "bar"); |
| |
| // Wrap it with braces |
| let v: Vec<String> = vec!["foo".to_string(), "bar".to_string()]; |
| let _s: String = (&*v.join("\n")).to_string(); |
| |
| format!("prepend {:+}", "s"); |
| } |