Update upstream source from tag 'upstream/1.52.1+dfsg1'

[rustc.git] / src / tools / clippy / tests / ui / redundant_clone.rs

diff --git a/src/tools/clippy/tests/ui/redundant_clone.rs b/src/tools/clippy/tests/ui/redundant_clone.rs
new file mode 100644 (file)
index 0000000..b570274
--- /dev/null
+++ b/src/tools/clippy/tests/ui/redundant_clone.rs
@@ -0,0 +1,184 @@
+// run-rustfix
+// rustfix-only-machine-applicable
+
+#![allow(clippy::implicit_clone)]
+use std::ffi::OsString;
+use std::path::Path;
+
+fn main() {
+    let _s = ["lorem", "ipsum"].join(" ").to_string();
+
+    let s = String::from("foo");
+    let _s = s.clone();
+
+    let s = String::from("foo");
+    let _s = s.to_string();
+
+    let s = String::from("foo");
+    let _s = s.to_owned();
+
+    let _s = Path::new("/a/b/").join("c").to_owned();
+
+    let _s = Path::new("/a/b/").join("c").to_path_buf();
+
+    let _s = OsString::new().to_owned();
+
+    let _s = OsString::new().to_os_string();
+
+    // Check that lint level works
+    #[allow(clippy::redundant_clone)]
+    let _s = String::new().to_string();
+
+    let tup = (String::from("foo"),);
+    let _t = tup.0.clone();
+
+    let tup_ref = &(String::from("foo"),);
+    let _s = tup_ref.0.clone(); // this `.clone()` cannot be removed
+
+    {
+        let x = String::new();
+        let y = &x;
+
+        let _x = x.clone(); // ok; `x` is borrowed by `y`
+
+        let _ = y.len();
+    }
+
+    let x = (String::new(),);
+    let _ = Some(String::new()).unwrap_or_else(|| x.0.clone()); // ok; closure borrows `x`
+
+    with_branch(Alpha, true);
+    cannot_double_move(Alpha);
+    cannot_move_from_type_with_drop();
+    borrower_propagation();
+    not_consumed();
+    issue_5405();
+    manually_drop();
+}
+
+#[derive(Clone)]
+struct Alpha;
+fn with_branch(a: Alpha, b: bool) -> (Alpha, Alpha) {
+    if b { (a.clone(), a.clone()) } else { (Alpha, a) }
+}
+
+fn cannot_double_move(a: Alpha) -> (Alpha, Alpha) {
+    (a.clone(), a)
+}
+
+struct TypeWithDrop {
+    x: String,
+}
+
+impl Drop for TypeWithDrop {
+    fn drop(&mut self) {}
+}
+
+fn cannot_move_from_type_with_drop() -> String {
+    let s = TypeWithDrop { x: String::new() };
+    s.x.clone() // removing this `clone()` summons E0509
+}
+
+fn borrower_propagation() {
+    let s = String::new();
+    let t = String::new();
+
+    {
+        fn b() -> bool {
+            unimplemented!()
+        }
+        let _u = if b() { &s } else { &t };
+
+        // ok; `s` and `t` are possibly borrowed
+        let _s = s.clone();
+        let _t = t.clone();
+    }
+
+    {
+        let _u = || s.len();
+        let _v = [&t; 32];
+        let _s = s.clone(); // ok
+        let _t = t.clone(); // ok
+    }
+
+    {
+        let _u = {
+            let u = Some(&s);
+            let _ = s.clone(); // ok
+            u
+        };
+        let _s = s.clone(); // ok
+    }
+
+    {
+        use std::convert::identity as id;
+        let _u = id(id(&s));
+        let _s = s.clone(); // ok, `u` borrows `s`
+    }
+
+    let _s = s.clone();
+    let _t = t.clone();
+
+    #[derive(Clone)]
+    struct Foo {
+        x: usize,
+    }
+
+    {
+        let f = Foo { x: 123 };
+        let _x = Some(f.x);
+        let _f = f.clone();
+    }
+
+    {
+        let f = Foo { x: 123 };
+        let _x = &f.x;
+        let _f = f.clone(); // ok
+    }
+}
+
+fn not_consumed() {
+    let x = std::path::PathBuf::from("home");
+    let y = x.clone().join("matthias");
+    // join() creates a new owned PathBuf, does not take a &mut to x variable, thus the .clone() is
+    // redundant. (It also does not consume the PathBuf)
+
+    println!("x: {:?}, y: {:?}", x, y);
+
+    let mut s = String::new();
+    s.clone().push_str("foo"); // OK, removing this `clone()` will change the behavior.
+    s.push_str("bar");
+    assert_eq!(s, "bar");
+
+    let t = Some(s);
+    // OK
+    if let Some(x) = t.clone() {
+        println!("{}", x);
+    }
+    if let Some(x) = t {
+        println!("{}", x);
+    }
+}
+
+#[allow(clippy::clone_on_copy)]
+fn issue_5405() {
+    let a: [String; 1] = [String::from("foo")];
+    let _b: String = a[0].clone();
+
+    let c: [usize; 2] = [2, 3];
+    let _d: usize = c[1].clone();
+}
+
+fn manually_drop() {
+    use std::mem::ManuallyDrop;
+    use std::sync::Arc;
+
+    let a = ManuallyDrop::new(Arc::new("Hello!".to_owned()));
+    let _ = a.clone(); // OK
+
+    let p: *const String = Arc::into_raw(ManuallyDrop::into_inner(a));
+    unsafe {
+        Arc::from_raw(p);
+        Arc::from_raw(p);
+    }
+}