rust-clippy/tests/ui/format.rs
2018-10-11 12:16:22 +02:00

69 lines
2.2 KiB
Rust
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![allow(clippy::print_literal)]
#![warn(clippy::useless_format)]
struct Foo(pub String);
macro_rules! foo {
($($t:tt)*) => (Foo(format!($($t)*)))
}
fn main() {
format!("foo");
format!("{}", "foo");
format!("{:?}", "foo"); // don't warn about debug
format!("{:8}", "foo");
format!("{:width$}", "foo", width = 8);
format!("{:+}", "foo"); // warn when the format makes no difference
format!("{:<}", "foo"); // warn when the format makes no difference
format!("foo {}", "bar");
format!("{} bar", "foo");
let arg: String = "".to_owned();
format!("{}", arg);
format!("{:?}", arg); // don't warn about debug
format!("{:8}", arg);
format!("{:width$}", arg, width = 8);
format!("{:+}", arg); // warn when the format makes no difference
format!("{:<}", arg); // warn when the format makes no difference
format!("foo {}", arg);
format!("{} bar", arg);
// we dont want to warn for non-string args, see #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);
format!("{}", 42.to_string());
let x = std::path::PathBuf::from("/bar/foo/qux");
format!("{}", x.display().to_string());
}