#![feature(plugin)] #![plugin(clippy)] #[deny(cmp_owned)] #[allow(unnecessary_operation)] fn main() { fn with_to_string(x : &str) { x != "foo".to_string(); //~^ ERROR this creates an owned instance just for comparison. Consider using `x != "foo"` to compare without allocation "foo".to_string() != x; //~^ ERROR this creates an owned instance just for comparison. Consider using `"foo" != x` to compare without allocation } let x = "oh"; with_to_string(x); x != "foo".to_owned(); //~ERROR this creates an owned instance // removed String::from_str(..), as it has finally been removed in 1.4.0 // as of 2015-08-14 x != String::from("foo"); //~ERROR this creates an owned instance 42.to_string() == "42"; }