Rollup merge of #71948 - csmoe:issue-61076, r=oli-obk

Suggest to await future before ? operator

Closes https://github.com/rust-lang/rust/issues/71811
cc #61076

src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr

@@ -237,7 +237,10 @@ error[E0277]: the `?` operator can only be applied to values that implement `std
   --> $DIR/incorrect-syntax-suggestions.rs:16:19
    |
 LL |     let _ = await bar()?;
-   |                   ^^^^^^ the `?` operator cannot be applied to type `impl std::future::Future`
+   |                   ^^^^^^
+   |                   |
+   |                   the `?` operator cannot be applied to type `impl std::future::Future`
+   |                   help: consider using `.await` here: `bar().await?`
    |
    = help: the trait `std::ops::Try` is not implemented for `impl std::future::Future`
    = note: required by `std::ops::Try::into_result`

src/test/ui/async-await/issue-61076.rs

@@ -0,0 +1,32 @@
+// edition:2018
+
+use core::future::Future;
+use core::pin::Pin;
+use core::task::{Context, Poll};
+
+struct T;
+
+impl Future for T {
+    type Output = Result<(), ()>;
+
+    fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
+        Poll::Pending
+    }
+}
+
+async fn foo() -> Result<(), ()> {
+    Ok(())
+}
+
+async fn bar() -> Result<(), ()> {
+    foo()?; //~ ERROR the `?` operator can only be applied to values that implement `std::ops::Try`
+    Ok(())
+}
+
+async fn baz() -> Result<(), ()> {
+    let t = T;
+    t?; //~ ERROR the `?` operator can only be applied to values that implement `std::ops::Try`
+    Ok(())
+}
+
+fn main() {}

src/test/ui/async-await/issue-61076.stderr

@@ -0,0 +1,27 @@
+error[E0277]: the `?` operator can only be applied to values that implement `std::ops::Try`
+  --> $DIR/issue-61076.rs:22:5
+   |
+LL |     foo()?;
+   |     ^^^^^^
+   |     |
+   |     the `?` operator cannot be applied to type `impl std::future::Future`
+   |     help: consider using `.await` here: `foo().await?`
+   |
+   = help: the trait `std::ops::Try` is not implemented for `impl std::future::Future`
+   = note: required by `std::ops::Try::into_result`
+
+error[E0277]: the `?` operator can only be applied to values that implement `std::ops::Try`
+  --> $DIR/issue-61076.rs:28:5
+   |
+LL |     t?;
+   |     ^^
+   |     |
+   |     the `?` operator cannot be applied to type `T`
+   |     help: consider using `.await` here: `t.await?`
+   |
+   = help: the trait `std::ops::Try` is not implemented for `T`
+   = note: required by `std::ops::Try::into_result`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.

src/test/ui/async-await/try-on-option-in-async.rs

@@ -7,7 +7,8 @@ async fn an_async_block() -> u32 {
         let x: Option<u32> = None;
         x?; //~ ERROR the `?` operator
         22
-    }.await
+    }
+    .await
 }
 
 async fn async_closure_containing_fn() -> u32 {

src/test/ui/async-await/try-on-option-in-async.stderr

@@ -7,14 +7,14 @@ LL | |         let x: Option<u32> = None;
 LL | |         x?;
    | |         ^^ cannot use the `?` operator in an async block that returns `{integer}`
 LL | |         22
-LL | |     }.await
+LL | |     }
    | |_____- this function should return `Result` or `Option` to accept `?`
    |
    = help: the trait `std::ops::Try` is not implemented for `{integer}`
    = note: required by `std::ops::Try::from_error`
 
 error[E0277]: the `?` operator can only be used in an async closure that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
-  --> $DIR/try-on-option-in-async.rs:16:9
+  --> $DIR/try-on-option-in-async.rs:17:9
    |
 LL |       let async_closure = async || {
    |  __________________________________-
@@ -29,7 +29,7 @@ LL | |     };
    = note: required by `std::ops::Try::from_error`
 
 error[E0277]: the `?` operator can only be used in an async function that returns `Result` or `Option` (or another type that implements `std::ops::Try`)
-  --> $DIR/try-on-option-in-async.rs:25:5
+  --> $DIR/try-on-option-in-async.rs:26:5
    |
 LL |   async fn an_async_function() -> u32 {
    |  _____________________________________-