Rollup merge of #118419 - compiler-errors:await-span2, r=cjgillot

Eagerly return `ExprKind::Err` on `yield`/`await` in wrong coroutine context

This PR does 2 things:
1. Refuses to lower `.await` or `yield` when we are outside of the right coroutine context for the operator. Instead, we lower to `hir::ExprKind::Err`, to silence subsequent redundant errors.
2. Reworks a bit of the span tracking in `LoweringContext` to fix a bad span when we have something like `let x = [0; async_fn().await]` where the `await` is inside of an anon const. The span for the "item" still kinda sucks, since it overlaps with the `await` span, but at least it's accurate.

4 files changed, 8 insertions, 51 deletions

diff --git a/tests/ui/async-await/issue-70594.rs b/tests/ui/async-await/issue-70594.rs
index 9e7c5847b3b..4c8209348b3 100644
--- a/tests/ui/async-await/issue-70594.rs
+++ b/tests/ui/async-await/issue-70594.rs
@@ -3,9 +3,6 @@
 async fn fun() {
     [1; ().await];
     //~^ error: `await` is only allowed inside `async` functions and blocks
-    //~| error: `.await` is not allowed in a `const`
-    //~| error: `.await` is not allowed in a `const`
-    //~| error: `()` is not a future
 }
 
 fn main() {}
diff --git a/tests/ui/async-await/issue-70594.stderr b/tests/ui/async-await/issue-70594.stderr
index 9866e00bb83..aed99ec3f1f 100644
--- a/tests/ui/async-await/issue-70594.stderr
+++ b/tests/ui/async-await/issue-70594.stderr
@@ -1,37 +1,12 @@
 error[E0728]: `await` is only allowed inside `async` functions and blocks
   --> $DIR/issue-70594.rs:4:12
    |
-LL | async fn fun() {
-   |          --- this is not `async`
 LL |     [1; ().await];
-   |            ^^^^^ only allowed inside `async` functions and blocks
+   |         ---^^^^^
+   |         |  |
+   |         |  only allowed inside `async` functions and blocks
+   |         this is not `async`
 
-error[E0744]: `.await` is not allowed in a `const`
-  --> $DIR/issue-70594.rs:4:9
-   |
-LL |     [1; ().await];
-   |         ^^^^^^^^
-
-error[E0744]: `.await` is not allowed in a `const`
-  --> $DIR/issue-70594.rs:4:12
-   |
-LL |     [1; ().await];
-   |            ^^^^^
-
-error[E0277]: `()` is not a future
-  --> $DIR/issue-70594.rs:4:12
-   |
-LL |     [1; ().await];
-   |           -^^^^^
-   |           ||
-   |           |`()` is not a future
-   |           help: remove the `.await`
-   |
-   = help: the trait `Future` is not implemented for `()`
-   = note: () must be a future or must implement `IntoFuture` to be awaited
-   = note: required for `()` to implement `IntoFuture`
-
-error: aborting due to 4 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0277, E0728, E0744.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0728`.
diff --git a/tests/ui/async-await/issues/issue-62009-1.rs b/tests/ui/async-await/issues/issue-62009-1.rs
index 40ccf25712e..51d216408d7 100644
--- a/tests/ui/async-await/issues/issue-62009-1.rs
+++ b/tests/ui/async-await/issues/issue-62009-1.rs
@@ -11,5 +11,4 @@ fn main() {
     //~^ ERROR `await` is only allowed inside `async` functions and blocks
     (|_| 2333).await;
     //~^ ERROR `await` is only allowed inside `async` functions and blocks
-    //~| ERROR is not a future
 }
diff --git a/tests/ui/async-await/issues/issue-62009-1.stderr b/tests/ui/async-await/issues/issue-62009-1.stderr
index bb617d09076..02933f4f2f2 100644
--- a/tests/ui/async-await/issues/issue-62009-1.stderr
+++ b/tests/ui/async-await/issues/issue-62009-1.stderr
@@ -24,20 +24,6 @@ LL | fn main() {
 LL |     (|_| 2333).await;
    |                ^^^^^ only allowed inside `async` functions and blocks
 
-error[E0277]: `{closure@$DIR/issue-62009-1.rs:12:6: 12:9}` is not a future
-  --> $DIR/issue-62009-1.rs:12:16
-   |
-LL |     (|_| 2333).await;
-   |               -^^^^^
-   |               ||
-   |               |`{closure@$DIR/issue-62009-1.rs:12:6: 12:9}` is not a future
-   |               help: remove the `.await`
-   |
-   = help: the trait `Future` is not implemented for closure `{closure@$DIR/issue-62009-1.rs:12:6: 12:9}`
-   = note: {closure@$DIR/issue-62009-1.rs:12:6: 12:9} must be a future or must implement `IntoFuture` to be awaited
-   = note: required for `{closure@$DIR/issue-62009-1.rs:12:6: 12:9}` to implement `IntoFuture`
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0277, E0728.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0728`.