New upstream version 1.48.0~beta.8+dfsg1

[rustc.git] / src / test / ui / suggestions / expected-boxed-future-isnt-pinned.stderr

error[E0308]: mismatched types
  --> $DIR/expected-boxed-future-isnt-pinned.rs:11:5
   |
LL | fn foo<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> {
   |        - this type parameter                            ----------------------- expected `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>` because of return type
LL |     // We could instead use an `async` block, but this way we have no std spans.
LL |     x
   |     ^
   |     |
   |     expected struct `Pin`, found type parameter `F`
   |     help: you need to pin and box this expression: `Box::pin(x)`
   |
   = note:      expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>`
           found type parameter `F`

error[E0308]: mismatched types
  --> $DIR/expected-boxed-future-isnt-pinned.rs:18:5
   |
LL | fn bar<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> {
   |                                                         ----------------------- expected `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>` because of return type
LL |     Box::new(x)
   |     ^^^^^^^^^^^ expected struct `Pin`, found struct `Box`
   |
   = note: expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>`
              found struct `Box<F>`
   = help: use `Box::pin`

error[E0308]: mismatched types
  --> $DIR/expected-boxed-future-isnt-pinned.rs:22:14
   |
LL | fn baz<F: Future<Output=i32> + Send + 'static>(x: F) -> BoxFuture<'static, i32> {
   |        - this type parameter
LL |     Pin::new(x)
   |              ^
   |              |
   |              expected struct `Box`, found type parameter `F`
   |              help: store this in the heap by calling `Box::new`: `Box::new(x)`
   |
   = note:      expected struct `Box<dyn Future<Output = i32> + Send>`
           found type parameter `F`
   = note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html

error[E0277]: `dyn Future<Output = i32> + Send` cannot be unpinned
  --> $DIR/expected-boxed-future-isnt-pinned.rs:22:5
   |
LL |     Pin::new(x)
   |     ^^^^^^^^ the trait `Unpin` is not implemented for `dyn Future<Output = i32> + Send`
   |
   = note: required by `Pin::<P>::new`

error[E0277]: `dyn Future<Output = i32> + Send` cannot be unpinned
  --> $DIR/expected-boxed-future-isnt-pinned.rs:27:5
   |
LL |     Pin::new(Box::new(x))
   |     ^^^^^^^^ the trait `Unpin` is not implemented for `dyn Future<Output = i32> + Send`
   |
   = note: required by `Pin::<P>::new`

error[E0308]: mismatched types
  --> $DIR/expected-boxed-future-isnt-pinned.rs:31:5
   |
LL |   fn zap() -> BoxFuture<'static, i32> {
   |               ----------------------- expected `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>` because of return type
LL | /     async {
LL | |         42
LL | |     }
   | |_____^ expected struct `Pin`, found opaque type
   | 
  ::: $SRC_DIR/core/src/future/mod.rs:LL:COL
   |
LL |   pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
   |                                             ------------------------------- the found opaque type
   |
   = note:   expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>`
           found opaque type `impl Future`
help: you need to pin and box this expression
   |
LL |     Box::pin(async {
LL |         42
LL |     })
   |

error: aborting due to 6 previous errors

Some errors have detailed explanations: E0277, E0308.
For more information about an error, try `rustc --explain E0277`.