#![warn(needless_pass_by_value)] #![allow(dead_code, single_match, if_let_redundant_pattern_matching, many_single_char_names)] use std::borrow::Borrow; use std::convert::AsRef; // `v` should be warned // `w`, `x` and `y` are allowed (moved or mutated) fn foo(v: Vec, w: Vec, mut x: Vec, y: Vec) -> Vec { assert_eq!(v.len(), 42); consume(w); x.push(T::default()); y } fn consume(_: T) {} struct Wrapper(String); fn bar(x: String, y: Wrapper) { assert_eq!(x.len(), 42); assert_eq!(y.0.len(), 42); } // V implements `Borrow`, but should be warned correctly fn test_borrow_trait, U: AsRef, V>(t: T, u: U, v: V) { println!("{}", t.borrow()); println!("{}", u.as_ref()); consume(&v); } // ok fn test_fn i32>(f: F) { f(1); } // x should be warned, but y is ok fn test_match(x: Option>, y: Option>) { match x { Some(Some(_)) => 1, // not moved _ => 0, }; match y { Some(Some(s)) => consume(s), // moved _ => (), }; } // x and y should be warned, but z is ok fn test_destructure(x: Wrapper, y: Wrapper, z: Wrapper) { let Wrapper(s) = z; // moved let Wrapper(ref t) = y; // not moved let Wrapper(_) = y; // still not moved assert_eq!(x.0.len(), s.len()); println!("{}", t); } trait Foo {} // `S: Serialize` is allowed to be passed by value, since a caller can pass `&S` instead trait Serialize {} impl<'a, T> Serialize for &'a T where T: Serialize {} impl Serialize for i32 {} fn test_blanket_ref(_foo: T, _serializable: S) {} fn issue_2114(s: String, t: String, u: Vec, v: Vec) { s.capacity(); let _ = t.clone(); u.capacity(); let _ = v.clone(); } struct S(T, U); impl S { fn foo( self, // taking `self` by value is always allowed s: String, t: String, ) -> usize { s.len() + t.capacity() } fn bar( _t: T, // Ok, since `&T: Serialize` too ) { } fn baz( &self, _u: U, _s: Self, ) { } } fn main() {}