#![warn(clippy::write_literal)] #![allow(clippy::uninlined_format_args, unused_must_use)] use std::io::Write; fn main() { let mut v = Vec::new(); // these should be fine write!(v, "Hello"); writeln!(v, "Hello"); let world = "world"; writeln!(v, "Hello {}", world); writeln!(v, "Hello {world}", world = world); writeln!(v, "3 in hex is {:X}", 3); writeln!(v, "2 + 1 = {:.4}", 3); writeln!(v, "2 + 1 = {:5.4}", 3); writeln!(v, "Debug test {:?}", "hello, world"); writeln!(v, "{0:8} {1:>8}", "hello", "world"); writeln!(v, "{1:8} {0:>8}", "hello", "world"); writeln!(v, "{foo:8} {bar:>8}", foo = "hello", bar = "world"); writeln!(v, "{bar:8} {foo:>8}", foo = "hello", bar = "world"); writeln!(v, "{number:>width$}", number = 1, width = 6); writeln!(v, "{number:>0width$}", number = 1, width = 6); writeln!(v, "{} of {:b} people know binary, the other half doesn't", 1, 2); writeln!(v, "10 / 4 is {}", 2.5); writeln!(v, "2 + 1 = {}", 3); writeln!(v, "From expansion {}", stringify!(not a string literal)); // these should throw warnings write!(v, "Hello {}", "world"); //~^ ERROR: literal with an empty format string //~| NOTE: `-D clippy::write-literal` implied by `-D warnings` writeln!(v, "Hello {} {}", world, "world"); //~^ ERROR: literal with an empty format string writeln!(v, "Hello {}", "world"); //~^ ERROR: literal with an empty format string writeln!(v, "{} {:.4}", "a literal", 5); //~^ ERROR: literal with an empty format string // positional args don't change the fact // that we're using a literal -- this should // throw a warning writeln!(v, "{0} {1}", "hello", "world"); //~^ ERROR: literal with an empty format string //~| ERROR: literal with an empty format string writeln!(v, "{1} {0}", "hello", "world"); //~^ ERROR: literal with an empty format string //~| ERROR: literal with an empty format string // named args shouldn't change anything either writeln!(v, "{foo} {bar}", foo = "hello", bar = "world"); //~^ ERROR: literal with an empty format string //~| ERROR: literal with an empty format string writeln!(v, "{bar} {foo}", foo = "hello", bar = "world"); //~^ ERROR: literal with an empty format string //~| ERROR: literal with an empty format string }