no-send-res-ports.rs

Author: Kivooeo

tests/ui/threads-sendsync/rc-is-not-send.rs

@@ -1,28 +1,32 @@
-use std::thread;
+//! Test that `Rc<T>` cannot be sent between threads.
+//!
+//! `Rc<T>` uses non-atomic reference counting, so it's not safe to send between
+//! threads. This test makes sure the compiler catches attempts to move `Rc<T>`
+//! into a spawned thread and produces a helpful error message.
+
 use std::rc::Rc;
+use std::thread;
 
 #[derive(Debug)]
 struct Port<T>(Rc<T>);
 
-fn main() {
-    #[derive(Debug)]
-    struct Foo {
-      _x: Port<()>,
-    }
+#[derive(Debug)]
+struct Foo {
+    _x: Port<()>,
+}
 
-    impl Drop for Foo {
-        fn drop(&mut self) {}
-    }
+impl Drop for Foo {
+    fn drop(&mut self) {}
+}
 
-    fn foo(x: Port<()>) -> Foo {
-        Foo {
-            _x: x
-        }
-    }
+fn foo(x: Port<()>) -> Foo {
+    Foo { _x: x }
+}
 
+fn main() {
     let x = foo(Port(Rc::new(())));
 
-    thread::spawn(move|| {
+    thread::spawn(move || {
         //~^ ERROR `Rc<()>` cannot be sent between threads safely
         let y = x;
         println!("{:?}", y);

tests/ui/threads-sendsync/rc-is-not-send.stderr

@@ -1,10 +1,10 @@
 error[E0277]: `Rc<()>` cannot be sent between threads safely
-  --> $DIR/no-send-res-ports.rs:25:19
+  --> $DIR/rc-is-not-send.rs:29:19
    |
-LL |       thread::spawn(move|| {
-   |       ------------- ^-----
+LL |       thread::spawn(move || {
+   |       ------------- ^------
    |       |             |
-   |  _____|_____________within this `{closure@$DIR/no-send-res-ports.rs:25:19: 25:25}`
+   |  _____|_____________within this `{closure@$DIR/rc-is-not-send.rs:29:19: 29:26}`
    | |     |
    | |     required by a bound introduced by this call
 LL | |
@@ -13,22 +13,22 @@ LL | |         println!("{:?}", y);
 LL | |     });
    | |_____^ `Rc<()>` cannot be sent between threads safely
    |
-   = help: within `{closure@$DIR/no-send-res-ports.rs:25:19: 25:25}`, the trait `Send` is not implemented for `Rc<()>`
+   = help: within `{closure@$DIR/rc-is-not-send.rs:29:19: 29:26}`, the trait `Send` is not implemented for `Rc<()>`
 note: required because it appears within the type `Port<()>`
-  --> $DIR/no-send-res-ports.rs:5:8
+  --> $DIR/rc-is-not-send.rs:11:8
    |
 LL | struct Port<T>(Rc<T>);
    |        ^^^^
 note: required because it appears within the type `Foo`
-  --> $DIR/no-send-res-ports.rs:9:12
+  --> $DIR/rc-is-not-send.rs:14:8
    |
-LL |     struct Foo {
-   |            ^^^
+LL | struct Foo {
+   |        ^^^
 note: required because it's used within this closure
-  --> $DIR/no-send-res-ports.rs:25:19
+  --> $DIR/rc-is-not-send.rs:29:19
    |
-LL |     thread::spawn(move|| {
-   |                   ^^^^^^
+LL |     thread::spawn(move || {
+   |                   ^^^^^^^
 note: required by a bound in `spawn`
   --> $SRC_DIR/std/src/thread/mod.rs:LL:COL